If you can learn to handle the pressure of competition, then you will start to swim to your potential. I thought you'd never ask. To swim fast under pressure you have to learn to relax. The biggest secret to swimming fast when it counts the most is to keep yourself loose and calm. The more relaxed that you are, the faster you'll go.
Relaxation is the key to speed in the pool.
Unfortunately, not too many swimmers understand this important connection. As a result, they go into their races and put far too much pressure on themselves. It's these kinds of pre-race thoughts which will make it impossible for you to relax and, as a result, rob you of your speed. The bigger the race, the more important it is for you to stay cool and calm before the start. This should be your goal before every one of your important races.