When making cupcakes there are a few things you need to remember for the perfect cupcake....

Beat sugar and butter together well untill light and fluffy. Slowly incorporate the eggs, one at a time. Then when adding the milk (I normally add the vanilla to the milk), flour add them in thirds ie. a third of flour and milk, mix till combined, add another 1/3 flour and milk, mix gently till combined etc. Be carefully not to over beat or this will toughen the cupcakes.