Make sure you don't leave out the good stuff. Talk about what you've done that shows how good you are. Keep it honest. You want to say as much as you can that's positive about yourself, but remember, if the resume works it will get you an interview with someone who will probably be looking right at it during that interview. Don't ever put in anything you can't defend, justify or comfortably explain.
Presentation IS important.
While the content of your resume is the most important thing, the visual appearance can make a big difference. If your resume is packed with great information, but appears crowded and hard to read, a busy executive might just not take the time to go through it with the care it deserves. Of course, but this is the real world. Use indentations, bullet points, and lots of white space. I like to put two or three short to medium sentences with each bullet point, although sometimes one impactful statement will stand alone.