I agree with Tartan...diagrams, photos and easy to understand text. I prefer lists to paragraphs - it's easier to find your place again when interrupted (frequently for me). I also like to see a list of all fabric requirements and all cutting requirements before the assembly instructions start. I hate to have to read several paragraphs only to find additional cutting instructions buried within. I like to have them all cut before I begin assembly. I also prefer easy to read type (
arial for instance) rather than serif (
times roman), and typed, not hand-written. Yardage/dimensions for multiple size quilts is a nice touch also.
Almost forgot - pressing tips for particular blocks (if any) are also very helpful!