Discover a Shipwreck.

Craft and place a sign.

Cure a zombie villager.

Gather all 16 colours of wool.

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

Befriend five wolves.

Play a music disc in a Jukebox.

Kill a skeleton with an arrow from more than 50 meters.

Throw diamonds at another player.

Ring the bell with a hostile enemy in the village.

Trade for the best possible price.

Use explosive barrels to kill 100 enemies

Stop starvation using Rotten Flesh.