I had to do a 25 yard breathhold for the aquarium, and I practiced in the pool while I was on vacation - initially I could not swim more than 15 yards or so. It just so happened that several divers from another aquarium happened to be in the pool at the same time and asked me what I was doing. I told them and we started chatting and soon they had no qualms about telling me what I was doing wrong. Which was mostly moving too much. Their point - how long can I sit and hold my breath - sixty seconds? ninety? I can reasonably swim 25 yards in at most 30-40 seconds, so if I need to breathe, it's because I'm expending too much energy. I was kicking a lot and using my arms. As I started to glide more, and KNOW that I could make it, I made it. The one other thing (mentioned) was relaxing ahead of time. When I went to the pool to practice right before the test, I was hyped up to start and couldn't make it all the way across the length of the pool (25 yards). I realized I needed to get into my "zen" place and THEN and ONLY THEN try it. I did so and made across with no problem. It's mind over matter, and as Lynne mentioned, technique (measured strokes and gliding).