Biomes are Meadows > Black Forest > Swamps > Mountains > Plains > Mistlands. If you haven't maxed the current Biome, don't hit the boss. Cautiously enter the next biome on your list until you have built up some gear. Steer way clear of a biome above the order listed above.

I have never used the spear. People have said it's too odd to handle. I always use bow first, axe if the get close. If you get some barnacles from a leviathian at sea (looks like a weird island), you can make a kick as dagger for sneak attacks.

Biggest tip I always forget... build a small hut, campfire and bed and set it as spawn near the boss fight.

have fun. Bonemass is next for me, after I build my big wood/stone/iron house. (pictures to come)