Rowdy Gaines has a website with a swim tips section.

Here is a link to some serious flipturn tips by Rowdy Gaines. My biggest transgression is tip number 1:

Tip #1 - Accelerate
Never slow down going into the wall. One of the big mistakes young (and old) swimmer make is, when they approach the wall, they begin to "measure" and their speed begins to decelerate. The more speed you have going into the turn the more momentum you will have coming off it. [Link]