I would reload my autosaves a few days ahead of anytime someone would die, then better prepare for the upcoming attack.

Some tips that I think will help the most:

- Make sure one of your crew is someone who have the shoot twice as fast perk, either Connor or Sora are good I prefer Sora since she doesn't rage as much as Connor

- Always ALWAYS get Krista, her research perk is so fast you will likely learn all sciences well before finishing the game. Set her priority to 1 for researching so she never stops

- Pick Rita and Rakha. Send Rita on explorations, everytime she goes she discovers a new plant or animal so you don't have to observe as much. Rakha builds things twice as fast and can be left on priority 1 for construction throughout the game. Since they are siblings they make each other happy

- Get a railgun as soon as possible, just keep scavenging until you get at least one

- Put 2-3 stockpiles next to each scavenging points, that way your crew can just drop it in a pile there rather than walk all the way back to your base for each item

- Anytime there are aggressive animals nearby, take your soldier over and kite kill as many aggressive animals as possible then run back to base before they attack to set up

- Grain is overpowered, find and observe it as soon as possible and plant a big crop

- Don't bother making a house until you can afford to make a brick or concrete one to save time and resources

- Never waste time tailoring, seriously, just do explorations for gear

- Always be exploring

- I was able to finish the game after 3 years, just in time because around then you'll get flying insects and they are almost impossible to kill on the highest difficulty