Construct a Nether Portal.

Construct a Dispenser.

Construct one type of each tool (one pickaxe, one spade, one axe and one hoe).

Befriend five wolves.

Use a saddle to ride a pig, then have the pig get hurt from fall damage while riding it.

Harvest some leather.

Attack and destroy a monster.

Use planks and sticks to make a sword.

Travel by minecart to a point at least 500m in a single direction from where you started.

Catch and cook a fish!

Construct a better pickaxe.

Bake a cake using wheat, sugar, milk and eggs!

Turn wheat into bread.

Use planks and sticks to make a hoe.

Smelt an iron ingot.

Construct a furnace out of eight cobblestone blocks.

Use planks and sticks to make a pickaxe.

Craft a workbench with four blocks of wooden planks.

Punch a tree until the block of wood pops out.

Open your inventory.