I learned this trick from Alton Brown. He's the guy on the Food Network show Good Eats.
When I'm making cookies and I need to pour 2 1/2 cups of flour from a bowl into the batter without making a mess, I do this:
I take a flimsy paper plate and pour about a third of the flour onto it. Then I fold the paper plate in half as I let the flour slide into the mixer. I repeat this until all the flour is mixed in.