Although no "one right way" exists to develop and format style sheets, some techniques prove more effective than others. Here are a few tips to get you started:

• Take care of the document-wide formatting first -- that is, specify the background image, background color, and font before you start specifying the nit-picky individual formatting.
• Add one or two styles at a time and test them. It's easier to troubleshoot just a few new styles than it is to troubleshoot a whole blob of new ones.
• Stay as simple as possible and expand gradually, as you need to. It's easier to add new styles one at a time than it is to backtrack and remove styles.
• You might here some web gurus bantering about style sheets and something called WYSIWYG (What you see is what you get). Theoretically, style sheets make the display of things uniform across every computer. Don't get caught up in the hype. You still don't have absolute control of the final appearance of the document because your readers might not have style-sheet-capable browsers, might have their browsers set not to use style sheets, or might override your formatting with their own preferred formatting.