Hello Kilo. First magic isn't an exact science, it's an art, so developing magic is more developing ones personal experience and expression of your own self and powers of expression in many ways. Going through spells as if they are recipes and expecting results is Hollywood sorcery, not actual life. It's not baking a cake, though I do have a collection of magical recipes like hazelnut bread I'm happy to share!
That being said (disclaimer ending) I have not read the book yet myself, but "Drawing Down the Moon" by Margot Adler is aparently a wonderful read and details witchcraft and Wicca as a religion, art, practice, and lifestyle.
Scott Cunningham is a reputable author when it comes to resources on the craft, such as his encyclopedia of herbs, or gems and metals.
I have read through some of "To ride a silver broomstick", and though it was authored to a more teenage audience, it is not entirely without credibility and can be useful.
Regarding sole mental and psychic information, and some exercises and techniques, Dion Fortune's "psychic self defense" is a good read, as is Henry Agrippa's "Of Geomancy" if you're interested in divination techniques.