I always start with the face/head of a character, but like any "How to Draw Manga" books, I draw it out as a stick figure if I don't know exactly how I want the chari placed on the page. I do agree that those books can be a little confusing and may not help very much. I say that the best practice is through looking at real things (as others have said already) and go from there. I do use my own hands occasionally, but it's not something that I rely on. Just work on using the things around you. That's my advice. ^,^ Good luck! If you wanna look at some of my work, check out my DA page
here