How can i improve my swimming speed?

so i'm not on a swim team, i just swim at my local gym. i worked with a trainer when i first learned to swim for a triathlon over the summer and she told me i had a very natural swim. i thought i was doing pretty good... when i found out going down and back in the pool (don't know the length..) in 54 seconds SUCKS. swim starts march first and i'm freaking out because i really want to make varsity but now i'm really concerned. how can i improve? i'm already swimming every day.