Drills and improving stroke mechanics are the biggest items I have found that reduce stroke count. You should throw in some stroke descent sets from time to time. Working on long smooth swimming is key for me.
Fabio,
Please go to the Training-Technique section of this web site (or use this link: www.usms.org/.../technique.htm), and read some of the articles there. I particular like the ones by Emmett Hines. You could also try www.H2Oustonswims.org/articles.html.
Matt
