Construct a Dispenser.

Acquire diamonds with your iron tools.

Create an Iron Golem.

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

Use the Totem of Undying to cheat death.

Use Shears to obtain wool from a Sheep.

Bribe a Dolphin.

Wear a full suit of Iron Armour.

Craft and place a Sign.

Destroy a secret wall.

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

Cook and eat a pork chop.