Befriend twenty stray Cats.

Feed a dolphin raw cod and have it lure you to treasure.

Craft and place a sign.

Build some bookshelves to improve your enchantment table.

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

Use planks and sticks to make a hoe.

Gain the trust of an Ocelot.

Create an Iron Golem.

Smelt wood trunks using charcoal to make more charcoal.

Use Shears to obtain wool from a sheep.

Craft and place a Flower Pot.

Breed two cows with wheat.