You'll fail a lot. I did in the beginning. Learning to build off simple mechanics can help solidify your footing in your world.

When creating a new world, it'll create large patches of one of two kinds of nastiness. First is the Corruption: Full of flying worm-like creatures in a land of shadows, Shadow Orbs pulsate with pure evil. The other is the Crimson: A living land of ichor, eyeballs, flesh, and bone where Demon Hearts throb with intelligent hunger. Both will slowly spread through Ice, Sand, Stone, and more.

Aside from those lands of evil, you'll encounter deserts, forests, sky islands, snowy lands, a jungle at one end of the world, and a dungeon at the opposite. The jungle is teeming with life that wants to end yours. The dungeon is teeming with death that wants to bring about yours.

Deep within the world, you'll find riches galore and danger to match. Deeper and deeper you'll dig, straight into the fiery underworld...and if you're willing to sacrifice your Guide to the boiling lakes of lava, the underworld will try to devour you, too. If you manage to emerge victorious, the world will be blessed with a land of Hallow...but such purity must be equally balanced by evil.

The creation of such extremes throws your world into Hard Mode...and Hard is an understatement. Every challenge you overcome will increase the danger...and the rewards...