This guide is spoiler free, in that I try not to give anything away that isn't immediately presented to the player on a new game. This isn't supposed to answer every question or let you beat the game, it's just stuff I wish I knew to prioritise when I first started playing.

Story stuff - If you don't want to spoil the story for yourself, there's some parts using a 4 digit code. Don't get impatient and look up the codes online, you'll find them in the game at the appropriate times.

• The Scanner tool is one of your first priorities to work towards, as is new swimming fins and air tank. I always keep my scanner on my hotkeys, it's easy to forget just how much can be scanned. You can miss opportunities to learn new ingredients or constructions which are vital to the game so check if you can scan anything nearby often! Also don't forget even some structures can be scanned!
  
  
• Enemies are mostly to be avoided, not fought. In general the game is about temporarily disabling, dodging or distracting enemies.
  
  
• Your first base you construct should be on the border of two "biomes" so you can exploit different resources quickly. As a rule of thumb I'd say build your first base 50-100m deep, then if you make a later base it should be 300m+. You'll also want it to be at least 200m horizontally away from the starting pod, no point building a base right next to it!
  
  
• Don't forget to build a radio receiver in your base, it's vital to progressing in the game. It's all too easy to forget to check it, then have a bunch of story thrown at you all at once.
  
  
• Air pipes are sort of annoying to use but vital to helping you explore early on. Place an air pump at the surface (or a different fixture on the side of a base) then hold an air pipe, swim away looking at the air pump to see the pipe placement appear, swim until you are as far as you can be then place the pipe.
  
  
• Stock up on a fresh free medkit any time you're near the lifepod.
  
  
• Always take some food and water with you, quite often you're just getting into somewhere interesting when your status bars start getting low.
  
  
• It's woth doing a large ingredient run for "Purified Water" all at once to stock up, otherwise water tends to be a little annoying when you're running low and need to make some up on the spot.
  
  
• Always take a spare locator beacon or two, it sucks finding an interesting or useful place then not knowing how to get back.
  
  
• Don't feel the need to craft too many batteries, as you can scavange many from an important explorable area in the first half of the game (you can get there after crafting a new wetsuit) If you're having trouble finding the place I'm talking about, spoil here for a hint Explore around the surface at the wrecked end of the Aurora once you have the radiation suit
  
  
• When you see a new resource for the first time collect as many as you can. Especially if the location is dangerous or far away. Even seemingly "useless" items can turn out to be vital to making important things. Some things can be grown or hatched too. There is a cargo upgrade to the first vehicle that is extremely helpful in carrying more loot back to your base. It's quite annoying to get back from a dangerous far off journey only to find you suddenly need a handful of resources from that area.
  
  
• Don't get too hung up on finding all of the pieces of a scannable technology all at once. If you can't find the pieces, try following some story prompts as they tend to lead you to new technology as the game progresses.
  
  
• When you get the first vehicle be careful where you park it. It's surprisingly easy to leave it near larger creatures that can wreck it whilst you're off doing a job nearby. Not fun to have a hard earned bit of gear "vanish" when you return to where you left it.
  
  
• When adding to your base keep an eye on the "HP". If you reach a negative amount the base will start to take damage and you'll be scrambling to quickly disassemble something to stop it.

Hopefully these help make your first game experience smoother, with less moments of "oh, I wish I knew to do Y before I spent a lot of time and effort doing X!"