This guide assumes that you are now able to reliably beat the Desert Dungeon using the Apprentice. Here's the basic gist of it (as described by others)...

• Roll for a shield on the shop. It will be equipped by the apprentice.
  
• Roll for a party of Apprentice, Paladin/Priest, Warrior/Tank
  
• Roll for at least the Alchemist Pet. Potions heal more as your character's HP grows. At a certain point, it becomes infinitely better than any healing done by Priests/Paladins.
  
• Keep stalling in the early game by keeping your Apprentice's attack low and defence high. Build your apprentice's stats in this order: Defence (3 stats around 30ish), HP (pre-100), Luck (to get high tier equipment), Offense (speed + either magic/physical attack), HP (post-100).
  
• After you built up all your stats, you can let the other teammates die. Always keep a stack of 1-4 potions. With your high HP and defence, your enemies will be dealing 1 damage (most of them) while 1 potion will heal you in the hundreds.
  
• Win. Go straight for the boss (unless farming kills) because he'll keep on spawning minions.

Pets

• Healer *
  
• Alchemist

* The healer is optional cause its heal sucks until you sacrifice good gear anyway. Near the end you won't be using it anymore due to amazing hp & potions. Sage works too.

Party

• Apprentice
  
• Priest
  
• Warrior/Tank

As you already know, the Apprentice levels up whenever you use his special. The Priest is there temporarily to help you survive the early phases of the desert dungeon as you buld up your Apprentice's defences. The Tank/Warrior will provide damage absorption necessary to survive that same early phase.

A few things you should know...

• Level ups by killing don't stack. The only time they stack is if you use the Apprentice special on top of a current level up.
  
• The damage absorbed by the Warrior/Tank will depend on his own defenses, not the defences of the ones he is protectic.

In case you are wondering, those were my final stats during my first time farming. You can do this method with much lower stats, just make sure you attack before the enemy and that you can kill everything in 1~3 hits.

Totem

Don't forget to get the defensive totem!

Having 2 experience runes equipped makes each kill give you a level. If you're having trouble getting these (they're the most important piece), try to aim for over 40 luck. You can make do with just one, but having 2 is so much better.

Ideally you'll want to have this at least several waves before the final one. That way you can get as close to your ideal damage before the actual farm begins.



You'll also want to have the best equipment by the time you reach the boss. You want to maximize that damage as soon as possible so you can sit back and relax as the game does the work for you (see video below).


* Take note that the kills don't get counted until after you end the instance, or in this case defeat the boss. The game seemed quite glitchy after about 20 minutes of continuous farm so I recommend ending the dungeon when things start to look weird (like no new spawns or if the game starts freezing).