There is no getting around it: swimming is a very technical sport. Probably the biggest difference between “fast” and “slow” swimmers is stroke efficiency. Time spent improving your stroke mechanics is very much worth the effort.
Cokie Lepinski, a 2010 USMS Kerry O’Brien Coaching Award winner, recently came out with an inexpensive eBook collecting 125 drills covering all four competitive strokes. Give it a try; you never know when you might find the drill that makes your stroke “click.”