The trick to making whipped cream is to use a really cold bowl and cold electric mixer (you don't have to use an electric mixer, but it is so much easier and faster). I put the bowl and beaters in the freezer for 15 minutes to a half hour to cool them off. Of course, you also have to be sure to use heavy cream or whipping cream. It won't work with regular milk, because there isn't enough fat.
Homemade Whipped Cream image by Stephanie Gallagher 2012, licensed to About.com Inc.