I use
fictfact.com and an Excel spreadsheet to keep track of my books. I like fictfact because it shows me the order of books in a series so that I can read series in order. I also use
fantastic fiction to check the order of series and order of releases of books--fantastic fiction is great, but it doesn't let you keep track of books you've read. In my Excel spreadsheet, I keep track of all the books I've read and when I read them.