Starting in 8th grade and continuing through high school, I kept a list of books to read, handwritten (of course -- it was The Olden Days), on lined looseleaf paper. Every time the list reached 100 items, I went back and crossed out those I had read and those that had lost their charm, rewrote the list, and started again. I probably should go back to that system, because I've never found one that works better. If I try to keep a notebook, it's never with me at the library. (I wish my library had a spot on their web site where you could enter things you want to read -- that way I could check on the computer when I'm there.) Carol and Pat are big fans of goodreads, but that hasn't clicked with me either. I have joined the iPhone generation, but I can't even remember to add things to my to-read list there!
Now, it's obvious that operator error is one of my major problems with keeping a book list -- but I'd love to hear how all of you keep track, organize your lists, and find your way to wonderful books.