Photos or illustrations with explanations that are step-by-step. Try not to use abbreviations. Even if something is repetitive, spell it out in order every time so people aren't trying to go back and forth within the pattern steps (more experienced people can just skip the repetitive parts). Make sure the photos or illustrations actually SHOW what to do. It really doesn't help when the photo is just of the back of a presser foot. Use a good close-up lens if necessary. Be sure to include amounts of fabric needed for different sizes. For those who like to do paper piecing, include that template (or those templates) as alternatives to using precuts. It would be great to have color photos of the finished product in several different color ways--maybe traditional prints, batiks, and brights. Test it out with a newbie or two to make sure you haven't missed anything.