Where you put your first base decides how much walking you do for the next twenty hours. There is no single perfect spot, but there is a checklist, and following it will save you a lot of pain.
The short answer
Flat Meadows, on the coast, near a Black Forest border. That combination covers almost everything you need.

Why each part matters
- Meadows because it is the safest biome. You will not be defending against anything serious while you learn.
- Flat because building on a slope is miserable. Use the
Hoe to level ground, but starting flat saves effort.
- Coastal because ore cannot go through portals. A dock means you can sail metal home instead of carrying it overland.
- Near the Black Forest because that is where copper, tin and cores are, and you will be making that trip constantly.
Things that seem clever and are not
Common base mistakes
- Building on the biome border. Greydwarfs wander over and chew your walls every night.
- Building inland because the view is nice. You will regret it the first time you mine a full load of copper.
- Sealing the fire in. Smoke does real damage. Leave a gap or build a chimney.
- Building too small. You will need room for a smelter, kiln, cauldron, chests and a portal hub sooner than you think.
A good starter layout
- A covered
Workbench with walls and a roof, or it will not work.
- A
Bed and a
Campfire with a smoke gap, for the Rested buff.
- Chests near the door, so you can dump loot without walking through the house.
- Space outside for a
Smelter and kiln, because both make smoke.
- A portal corner, once you have cores. Leave more space than you think.
Once you are settled, read the portal guide, because linking your base to wherever you are exploring is the biggest quality of life jump in the game.
Happy building!