One thing that has consistently amazed me about the editing process: absolutely glaring mistakes you don't catch until the third or fifth or tenth time through the text! Misplaced captions, dangling participles, missing letters, unclear instructions--we still found all of these kinds of things in the final read-through, even though we also had a professional copy editor go through it as well. Imagine being a beginner baker and reading that you should "lace the dough onto a baking sheet."
My chef friend Ron looked the manuscript over for me as well, and he gave it a good review, noting that every time he had a question about some part of the instructions, I would answer it in the next sentence. His mother also gave the book a thumbs-up, but she may have been unduly influenced by the monkey bread I sent home with Ron for me!