Collect any fish in a bucket.

Craft and place a Flower Pot.

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

Construct a Nether Portal.

Build some bookshelves to improve your enchantment table.

Use the Totem of Undying to cheat death.

Kill a Mob while wearing the same type of Mob Head.

Defeat an Evoker.

Use a Dried Kelp block as fuel in a furnace.

Dye your bed a different color.

Wear a full suit of Iron armour.

Swim in lava while having the Fire Resistance effect.

Smelt wood trunks using charcoal to make more charcoal.