Smelt wood trunks using charcoal to make more charcoal.

Use Shears to obtain wool from a sheep.

Acquire diamonds with your iron tools.

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

Use a Dried Kelp block as fuel in a furnace.

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

Catch and cook a fish!

Harvest some leather.

Attack and destroy a monster.

Construct a better pickaxe.

Construct a furnace out of eight cobblestone blocks.

Use planks and sticks to make a hoe.

Craft a workbench with four blocks of wooden planks.