Have you looked into Total Immersion swimming? Their whole philosophy is efficience/balanced swimming so you are fresh for the bike and run.
http://www.totalimmersion.net/
I know a lot of top triathletes who are doing this. I actually took a couple of lessons from them while traing for my first tri. Unfortunately, my baby is due to come the same week, so won't be able to do a tri until next year.
Anyway, they focus on body balance while swimming. I improved a lot after the lessons. Check it out.