Essential Gear
Make your first priority getting a Survival Knife, Scanner, and the Repair Tool.
Swimming
You swim faster on the surface than you do underwater.
Food and Water
Make sure you always keep at least one cured fish and one bottle of water with you at all times so you don't have to cut trips short due to hunger and thirst.
Avoid Drowning
To avoid drowning it is important that you always keep track of how deep you are and how long it might take you to surface if need be.
Radio Messages
Listen to the radio messages when they appear and go to the markers with the scanner, they give more of the story and around them will be important items to scan for blueprints.
Attacks
Although you may not be able to outfight or outrun everything, you will 95% of the time be able to outmaneuver it by moving sideways.
Lost River Entrance
You can safely enter Lost River through Blood Kelp Trench. The entrance can be found by navigating landmarks and you will not encounter any leviathans.
Radiation Suit
Remember that the Radiation Suit is needed to survive for long periods of time in areas close to the Aurora.
First Base
Build your first base near your Lifepod 5 and keep it simple, just build for function only.
Base Integrity
Putting reinforcements in a multipurpose room on the walls with the black triangle on the floor gives double strength ( 14 vs 7). This will help you make your base strong as possible while using the least Titanium. Remember though that when building above water level Bass Integrity is irrelevant.
Multipurpose Rooms
Multipurpose Rooms built directly on top of one another can be connected internally by only a lader. Ladders can be built in any of the four 'corners' that don't have a black triangle - or directly in the middle.
Base Windows
The windows of your base can be constructed on top of basic T, and X compartments. Windows can also be constructed on the ends of those compartments where a hatch would go. You can also construct a window or hatch on the end of a scanner room.
Base Hatches
Hatches can be constructed n the bottom of glass compartments and on the top and bottom of basic T, and X compartments.
Live Fish Storage
Live fish store indefinately without rotting in any storage container available, this includes bags, lockers, and vehicle storage.
Grav Traps
Grav Traps make an excellent 'fishing net' and have an endless supply of power once constructed.
Bioreactors
The Lantern Fruit tree is an excellent source for your Bioreactors, if you plant one or two in pots beside a reactor the fuel will always be immediately at hand.
Thermal Power
Thermal power provides 24/7 power as its not limited to day or night and does not require any fuel.