Here are some excellent books on style:

• Strunk & White, The Elements of Style
• Joseph M. Wiliams, Style: Lessons in Clarity and Grace
• William E. Blundell, The Art and Craft of Feature Writing
• Virginia Tufte, Artful Sentences

This website will forever cure you of using jargon (and give you a few chuckles, too):

• The Jargon Finder