Take each volume, go through the entire book, mark out what seems important to you. There are certain sleights you might specifically want to get better at. A good idea would be to take notes, if you can't keep the books or buy them, which I heavily recommend. Don't skip anything, not even the most basic things. A lot of material might be known beforehand, but reading will help you refine your techniques. Robert Giobbi's descriptions are extensive, but full of material. My best advice would be to borrow a single volume a month, and go through every bit of it. Card College is probably the best series for beginner to intermediate learners.