There are only four biomes in this game. You'll get this naturally if you're going for the other achievements, but the biomes are all accessible at pretty much any point, so this achievement can be gotten very early in the game if you want.
You start out in a sort of grass/hill biome, so right from the start, you're 25% of the way there. If you zoom out to the world map, it's easy to find the other three:
- The snow biomes are the big blue mountains at the poles
- The desert biome looks like yellow-colored land covered in cacti
- The "dark" biome is a black mountain with purplish glowing plants.
The dark one is a bit harder to find, so if you're at 75%, that's probably the one you're missing.
You don't need to actually land on the surface to be counted as "visiting" the biomes. If you fly or glide over the biome, it still counts.