Hello Sliders: Personally I would say the best remedy is practice, practice, practice...

The more you do it, the more comfortable you'll get at it. Plus, most interviewers ask similar questions. So each interview is an opportunity to refine the answers you give. During your interviews, pay attention to how your answers are being received. Do they seem to be working? Are they being met with positive responses? If not, then think about ways in which your responses can be tweaked in order to create a more positive impression.