Construct a Nether Portal.

Harvest some leather.

Tame an Ocelot.

Attack and destroy a monster.

Smelt Wood Trunks using Charcoal to make more Charcoal.

Breed two cows with wheat.

Brew a potion.

Power a Furnace with Lava.

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

Turn wheat into bread.

Construct a better pickaxe.

Craft a workbench with four blocks of wooden planks.