When I read books, I always look for patterns. Whether it is a stand alone book or serials. I often write a table comparing the books in a book series.
The Flamel Series for example, when you take the first letters of the titles, you will have A, M, S, N, W, E. If we rearrange the letters, we would have NEWMAS, SAWMEN, SWANME, etc.. Another one is the gender. Alchemyst is male, Magician is male, Sorceress is female, Necromancer is male, Warlock is male, Enchantress is female. That's male, male, female, male, male, female. Michael said that there's no pattern in his series but it's cool anyways..