Anyone with experience in large project management knows that little things make a big thing--and--"order" is more than sequence of activity. Fiction and Non-fiction writing has a lot in common, those books don't write themselves. Before you get started, you can eliminate a lot of the pain by knowing what you really want to say. Many writers admit to some suffering when they develop a new project, what they often mean to say is that frustration builds gradually over time when they don't know what to do next. That's why the much-dreaded outline matters, think of it as a road map can save you a lot of sleepless nights.
Everything from a novel to cookbooks can broken down in to chapters and individual sub-sections. Putting that on paper rots your brain--but--it gives you that much-needed road map to future victory. As bad as that sounds, you should still have some idea of how long it takes to do the actual writing, we're not all very fast or very slow; some of us just poke right on along at a middle-of-the-road pace. Knowing how long it takes you to write a chapter gives you a chance to do some simple math that suggests how long it may take to write the whole book. Example: If it takes you seven days to write 1 chapter, it's fair to say that it might take 25 weeks to write a 25 chapter manuscript.
With your road map and some sense of time commitments, you can more confidently go to the library or look online for the information you want, need, or just gotta have. It's not unusual for research to take longer than you expect. Remember the old saying about needles in haystacks, flipping through the paste of one book to find a single factoid can take days. I have actually spend several years (4+) gathering my research materials, just to write one book. That brings me to my last point, always give yourself more time; never force yourself to knock out a project so fast that it makes trouble for people around you. I'm not a lot of fun when I'm trying to hit self-imposed deadlines, so; I try to spread things out just enough to stay calm. Being honest with yourself about the scope and scale of what you are doing makes it easier to learn the things that drive you nuts.
Yes, I know how generalized all of this is. There is no one right way to develop your road map and set priorities--but--if you can do it in a way that works for you...many of your problems provide their own solution; especially when you understand that no book is ever as small or easy as you think it is going to be. Know that much, and the bigger projects are a little less scary.