The following 5 Achivments cant be missed since they are unlocked by playing the game

• The Plot Thickens - Finish the first part of the Story
  
• Reunited - Finish the secound part of the Story
  
• A Detective's End - Finish the third part of the Story
  
• Only One Thing Left to Do... - Finish the Fourth part of the Story
  
• Thank You - Finish the Final Mission

These Achivments can be missed by progressing to far into the Story

• Master of Kamurocho
  
  For this Achivment you need to get all the other achivments.
  
  
• Fashionista
  This achivement is only unlockable during Akiyamas part of the story.
  During the Story you will get call from the manager of Elise, who asks for your help in recruiting new hostesses for the club.
  First is Hiyori and she is in front of the Millennium Tower.
  The second is Nanami and she is at the Cuez bar in the underground mall.
  The last one you can recruit is Kyoko and she is in the Bantam Bar in the Millennium Tower east.
  Now in order to get the Fashionista trophy in Yakuza 4 you have to get 23 different types of outfits for the girls.
  
  Here is the list of outfits you need one of each not one of each color.
  
  • One shoulder Dress
    
  • Charming Off shoulder dress
    
  • Belted Off shoulder dress
    
  • Off shoulder dress
    
  • Long Halter dress
    
  • Halter dress
    
  • Sexy dress
    
  • Gathered dress
    
  • Mermaid dress
    
  • Short halter dress
    
  • Two-piece dress
    
  • Long two-piece
    
  • Mini skirt dress
    
  • Layered dress
    
  • bubble dress
    
  • Lovely dress
    
  • Camisole dress
    
  • Crossover top dress
    
  • Ladies suit
    
  • Juniors Suit
    
  • Chinese dress
    
  • Maid outfit
    
  • Schoolgirl uniform
  
  Remember you need one of each category not every single one.
  
  
• Indomitable
  
  When you loose a fight a few times and the game asks you if you want to switch to easy mode, select no.
  

There are multiple achivment connected to Collectibles.

• Way of the Key Master
  Find 5 Locker keys and open the Lockers, There are 100 Locker Keys hidden troughout all of kamerucho.
  Here is a Link to a website where you can find all 50 locker Keys
  LINK[gamefaqs.gamespot.com]
  Here is a Link to a website where you can find all 50 Underground locker Keys LINK[gamefaqs.gamespot.com]
  
• Substory Novice
  
• Substory Helper
  
• Substory Lover
  
• Substory Champion
  Here is a Link to a website where you can find all substories and how to complete them
  LINK[gamefaqs.gamespot.com]
  
• Gourmet of Kamurocho
  You must order at least 1 item from each menu as listed below - note: Take out orders do not count you will need to eat order everything Eat-in!!
  To get this achivment you will need to eat at these restaurants
  
  • Sushi Gin, Showa St
    
  • Cuez Bar, Underground Mall
    
  • Cafe Alps, Nakamichi St
    
  • Watami, Nakamichi St
    
  • Pronto, Nakamichi St (Different sets of menu during Day and Night you will need to eat from both menus)
    
  • Smile Burger, Nakmichi St
    
  • Matsuya, Tenkaichi St or Taihei Blvd
    
  • Gelateria Kamurocho, Tenkaichi St
    
  • Bantam, Millennium Tower St. East
    
  • Kyushu No. 1 Star, Pink Alley
    
  • Shellac, Champion District
    
  • Earth Angel, Champion District
    
  • Kanrai, Shicifuku East
    
  • Underground Gourmet, Sewers near Eco-Store
  
  
• Revelation Seeker
  For this Achivment you have to unlock 3 Revaltations. Here is a list of all Revalation and how to get them. Each playable Charachter has 2-4 Revelations.
  
  
  • Akiyama
    
    • Essence of Triple Strike - This is the first that Mack will point you to directly. at the end choose "Those leaps and bounds were something else."
      
    • Essence of Comebacks - Go to the west entrance of Little Asia, just south of Beam. You'll see a trio of guys laughing about some "kung fu masters". Look into the alley of Little Asia at the couple walking.At the end select "Hm, counterattacking after someone breaks your guard."
      
    • Essence of Loin Reaving - On the Eastern Rooftops, you'll find a cop, a kidnapper, and a kid, in the southeast part near the exit to Pink Alley. Focus on the lady cop and select "Right in the jewels. That's gotta hurt..."
  • Saejima
    
    • Essence of Bell Ringing - go to the Underground Parking Lot and go the mid-south part. Look for area #104 and a black car with a guy sitting inside. Focus on him. Choose "Guy slammed straight into the wall."
      
    • Essence of Heavy Weapons - Go to the Docks and focus on the dude in the oil drum. Choose "Somethin' that heavy's sure to do damage."
      
    • Essence of Clotheslining - Go to the Nakamichi Alley Poppo. You'll see a guy harassing a girl. Focus on them. Choose "The momentum helped him land a big hit."
      
    • Essence of Smashing - Go to the west entrance of Little Asia, just south of Beam. You'll see a trio of guys laughing about some "kung fu masters". Look into the alley of Little Asia at the couple walking. Select "Damn, she kicked clean through his guard."
  • Tanimura
    
    • Essence of Guillotine Heel - Head to the Club SEGA at Theater Square. Look at the UFO Catchers and focus on the male of the couple. Choose "Hm, he hit one toy with the other to make it fall."
      
    • Essence of Ball and Chain - Go to the Hotel District south of the Taxi Stand. Instead of focusing on the girl, focus on the homeless guy at the vending machines. Choose "Backwards between the legs?"
      
    • Essence of Skull-Crushing - From the Taxi Stand at the end of Park Boulevard, go west and focus on the girl singing. Choose "He got clocked hard when he was off guard..."
  • Kiryu
    
    • Essence of Merciless Throwing - On the Eastern Rooftops, you'll find a cop, a kidnapper, and a kid, in the southeast part near the exit to Pink Alley. Focus on the lady cop and select "She really gave him the ol' one-two."
      
    • Essence of Taunting - Go to the Nakamichi Alley Poppo. You'll see a guy harassing a girl. Focus on them. Choose "A strong hit after a taunt, huh?"
    Once again you dont need all revalations for the achivment, 3 are enough
• Kameroucho Tree hugger this is a simple achivment you just need to pick up 20 pieces of trash around the city.

• Welcome to Sega
  Go to the Club Sega at the Theater Square and Play the following games (you dont have to win) to unlock the Achivment.
  1. UFO Catcher
  2. Boxcelios 2
  3. Boxcelios (play Boxcelios 2 three times as Akiyama to unlock)
  
• Boiled Turkey
  Go to the Mach Bowling ally on the west end of Theater Square.
  Choose to play a 10-frame game.
  Scoring 3 Strikes in a row is considered a Turkey which unlocks this trophy.
  
• TableTennis Pro
  The Table Tennis minigame is available at Yunosono Hot Springs situated at Park Blvd. Each session costs 1000 yen and is a best of 3-match. The first player to reach 11 points is the winner of the match
  .When you Heat meter fills, you can press the Y button on your controller (Trianlge with PS controller) to smash the ball which will automatically win you that rally (and a stimulating cutscene).
  
  Perform 3 smashes in a SINGLE ROUND to unlock this achivment

Here is a List of all Memos you need to find:

• Memos - Automatically unlocked
  
• Save Points - First use of a save point
  
• Action Icons - Talk to the man in front of Matsuya
  
• Recovering Health - Talk to the woman in Champion District
  
• Switching Main Characters - Talk to Date in New Serena during the Final Chapter
  
• Main Characters’ Possessions - Talk to Akiyama in New Serena during Final Chapter
  
• Using the L3 and R3 buttons - Talk to the man located on Showa St. East
  
• Maps - Kamurocho Rooftops West, talk to a man without sense of direction
  
• E-mail - Talk to the high school girl in Theater Square
  
• Using Items - Talk to the map with the big jacket in Theater Square
  
• Equippable Items (1/2) - Talk to the dangerous looking man in Shichifuku St.
  
• Equippable Items (2/2) - Conversation between a man on Pink St.
  
• Valuables - Park
  
• Akiyama's Fighting Style - Automatically obtained in Part 1 Chapter 1
  
• Seajima’s Fighting Style - Automatically obtained in Part 2 Chapter 1
  
• Tanimura’s Fighting Style - Automatically obtained in Part 3 Chapter 1
  
• Kiryu’s Fighting Style - Automatically obtained in Part 4 Chapter 1
  
• HEAT Actions - Park
  
• Kicking Objects - Talk to a man on Nakamichi St.
  
• Destructible Objects - Underground Theater B3, electrical room
  
• Chase Battles (Fleeing) - Kamurocho Rooftops West
  
• Chase Battles (Pursuing) - Theater Square
  
• Other Chase Battle Techniques - Kamurocho Rooftops West
  
• Exp Points and Leveling Up - Kamurocho Rooftops East, woman near east-most entrance
  
• Soul Points - Millennium Tower Underground.
  
• Revelations - Automatically obtained when you first meet Mack as Akiyama
  
• Daijiro Saigo's Training - Akiyama - Story Related, automatically obtained on Rooftops West as Akiyama
  
• Master's Helper - Saejima - Story Related, automatically obtained as Saejima
  
• Supporting Detective Nair - Obtained automatically after meeting Nair in Part 3 Chapter 2
  
• Developing HEAT Actions - During Battles, unlocked when you level up a HEAT Action
  
• First Person Mode - Go down manhole in Children’s Park, Shicifuku West St, and talk to old man down there.
  
• Akiyama's Friends - Kysuhu No. 1 Star Ramen
  
• Manholes - After meeting Kage the Florist in Chapter 4 of Saejima’s story
  
• Lockers (1/2) - Talk to the man in front of the Taihei Lockers
  
• Lockers (2/2) - Underground Mall, unlocked during a conversation with woman near the lockers
  
• Substories - Shellac, speak to the informant Aoki there
  
• "Complete" and "Incomplete" - Talk to a man outside Millennium Tower
  
• Effects of Getting Drunk - Unlocked during a conversation with a woman in Bantam
  
• Special Editions of Magazines - Talk to a man in Theater Square
  
• Rooftops - Tenkaichi St., talk to a man staring at the sky
  
• Underground - Showa St., unlocked in a conversation between a homeless man
  
• Works Kamiyama - Theatre Square
  
• NPCs Who Speak Foreign Languages - Talk to a man in one of the alleys
  
• Little Asia's Adopted Son - Tanimura - Foreign teacher standing outside carpark on Shicifuku Street
  
• Taxis - Talk to the man talking with a taxi driver in Hotel District
  
• MEB - Talk to the man inside MEB
  
• The Coliseum - Unlocked when you use the Coliseum
  
• Fighter Maker - Obtained automatically after agreeing to train Rookie Fighters at Sodachi’s Dojo
  
• IF7-R - Underground Theater B1, unlocked when you talk to the scientist
  
• How to Avoid Street Fights -Speak with the volunteer again in Theater Square that gave you memo “Police Scanner”
  
• Getting Help From People - Akiyama - Customer in Kyushu No. 1 Star Ramen
  
• Police Patrols - Saejima - Automatically obtained in Part 2 Chapter 4
  
• Police Scanner - Tanimuara - Automatically obtained in Part 3 Chapter 1
  
• Gang Encounters - Kiryu - Obtained after saving Kamurocho Guard in Theater Square while playing as Kiryu
  
• Getting Connected - Go to Naomi’s palace on Tenkaichi St. and speak to her until you unlock all three / Bonus Games / Online Rankings

Once you've gotten your last Memo, you must go into the Memo Menu in order for the achivment to unlock.

You will be introduced to Fighter Maker in Sadoshi’s Dojo during chapter 4 of Saejima’s story. The goal is to turn a stundent fighter in a top fighter in less then 50 turns.

Each turn you can choose 4 standard training modules to improve his Power, Speed, Technique and Max Health and 1 special module. For the special module you can choose options that will increase his Condition and Trust, fighting in mini Tournaments for Cash, Rest to regain Health, or participate in the Final Tournament.

At first you should improve his Condition and Trust by doing Stretching module and going out on Meetings. Choosing the right dialogue options during Meetings will teach him new skills that become useful during a fight as well.

Having a high Condition and Trust will increase the rate at which his stats improve. Once these two are at their max (Pink smiley for Condition and 2 Hearts for Trust), you’ll want to improve his basic stats and spar with him, while managing his health by resting every now and then. Zero health incur injuries and force him to rest until he recovers, in addition to resetting Condition/Trust. Once his stats are at the maximum, send him into the Final Tournament and watch him destroy anyone in his way.

After the Tournament the achivment should unlock.

• Walking Bank
  You have to aquire 10M yen, its best to do this after the main story in the premium mode, since you get 2M yen for beating the game on normal
  
• Fearsome Foursome
  For this achivement all 4 Playable charackters need to reach level 20, this is best done after the story in the Premium adventure mode.
  
• Akiyama the Hoarder
  Simple get 1Million Yen as Akyiama.
  
• Tanimura the Gambler
  Acquire 10,000 casino points with Tanimura.
  
• Saejima the Slinger
  Buy five guns playing as Saejima. The weapons dealer is on the rooftop near the mahjong parlour.
  
• Kiryu the Crusher
  Destroy 100 weapons you pick up playing as Kiryu. One easy way to throw empty Beer bottles at enemies during Chapter 2 in Part 4 of the game.You don't have to throw them at the enemies, just throw them at walls or stuff, cause they break right on the spot. And the sweet thing about the bottles in the box is that it's infinite.