I had problems keeping trim also in the begining.. I found I was thinking to much about it.. Once I got out of the pool and put it into "real world" practices. I found that I was in perfect trim and not thinking about it at all. i think overthinking is a big problem, and really what else is there to think about in a pool?? I had the same problem with my backwards kick, but I can still remember the time I was looking at a lobster and realized the surge was not throwing me anywhere and I was in perfect trim, with no hand movement.. It all comes with time.. Practice, Practice, Practice...