As soon as you can, cover your stockpiles and shelves of storage with a roof. Under the roof, resources continue to last longer or forever.
Always read the resource tooltips to learn how to utilize them, how long they last, and how to store them.
To prepare your first alien meals and emergency provisions (which increase happiness), build a fireplace or cook stove.
Save your emergency provisions for, well, emergencies as soon as you can prepare food using nearby ingredients (vegetable or meat soup).
Do not overcook. Have only 1 prepared meal for each survivor because cooked food spoils in a few days (You can instruct someone to cook vegetable soups on the stove until you have three or four.)
The Glitter caps are one of the most significant early-game resources (luminous orange mushrooms). As soon as you can, harvest them and establish a tiny farm. They can be utilized to manufacture long-lasting lamps, food, and medication. They can also be kept on shelves under the roof eternally.
Animal leather is the best fabric for early-game tailoring. can be used for bandages and armor-like gear. They are obtained by hunting Ulfen (the "large horned" animals) and simply hanging the hides to dry. Cotton (if you manage to land near some) cannot be used for armor, while vegetable leather requires a two-step, man-dependent procedure, first requiring the gathering of the skin bark (large purple plants).
Red meat is the best early game meat (hunted by Ulfen and Drakka). If dried, it can be used for a very long period. Without refrigeration, insect meat can't be kept for very long.
When "it's dark," either at night or during the day within a building without light, your survivors suffer a tiny happiness penalty and a significant working penalty (movement and manipulation). So make sure your primary shelters are always lit artificially. Shroom torches (manufactured from glitter caps) last 10 days longer than regular torches, requiring less time for "refueling" from your survivors.
By the beginning of autumn and later winter, you should have stored food (preserved if you can), medical supplies, and fuel (mainly sticks) because plants stop growing during these seasons and because laboring outside in the cold without suitable clothes will seriously impair your survivability.
If you finish an "enclosed" building by the first winter (base, walls, and roof), you'll find it much easier. Winters can be brutal, and if you don't have access to stoves or fireplaces for heat, your survivors may suffer greatly especially given that they will need to obtain resources outside on such chilly days. Depending on what is abundant in your beginning area, you can choose from a variety of materials.
For your early battles, employ guerrilla tactics. There will be some black bugs among them. Equip the survivor with the best fighting skill with a laser pistol as soon as you receive the first warning (the "aggressive animals" one), draft him, and move him closer to the bugs. While the gun is reloading, shoot one bug (some of the others will start to follow you), then begin to retreat. When everything is ready, shoot once more and begin to retreat. Repeat this until they are all gone.
Never hold off until the "Animal attack" alert. When that occurs, they will all attack at once, overwhelming you.
Try not to engage in melee combat. If someone is critically injured, this can lead to several health problems and a need for numerous medications.