Food keeps your hp and stamina high so keep some in your inventory no matter what you're doing, your base can get raided when you're in there so you don't want to be low on hp and stam building a roof then scrambling to get ready in the middle of a raid.

The Rested buff is a pretty good thing to have as it massively increases stamina and hp regen. You get it by spending some time in an enclosed area with a fire nearby. The more 'comfortable' that area is the longer the buff will last, things that add comfort being chairs rugs banners tables etc.

Explore your starting island, try to find a good spot in the meadows near the black forest and with good water access so you can get a boat for travel. Berry bushes don't respawn if you break them, they can't be planted, but they do grow more berries so be sure you got a good patch nearby. You want to be near the black forest so you can get to copper and tin easily, but don't be so near that mobs from there will agro. Don't enter the forest until you are ready, you gotta kill the first boss then you know you'll be ready.

Raids also come from the 'next boss up' so to say. Before the first boss raids will be medows area enemies, boars and lizards all easy to deal with. After him you will get monsters from the forest, greydwarfs and trolls, they can damage and destroy buildings so you should have a good outer wall up by then. An earthen wall and moat is best, you don't gotta fill it with water enemies aren't too good at climbing.

Almost forgot damage types. A simple wooden club can do wonders against skeletons, but won't do much to the blubber of a troll. A nice sharp arrow can pierce the trolls hide pretty deep, especially if you get him in the eye, but wont do much to a pile of walking bones.