Start learning the basics of magic, the basics: Expanded is a good start and you can look at other articles or forums to help you out.
Learning candles, herbs, and so on can help too.
After a studying for a while you can start casting spells. Remember werewolf, vampire, stopping time or any of that, magic can't do that. Magic can't change your body physical or change your DNA. Your human and remain human tell you die. Why your spell not working? Well, you didn't study the basics long enough, or you didn't wait long enough for the spell to work. Spells don't work fast, so give it a few weeks. I hope this helps you.