Have you learned all the basics? If yes do you truly believe in what your doing? If you have any doubt at all your spells will not work. Also practice practice practice your meditating and visualizing those are very important when doing a spell.
Here is a list of the Basics
The basics Tools,Meditation, Visualization, Focus, Moon Phases, Colors, Days, grounding and centering, power flow, Elements, circle casting, Charkas
This link is for the Basics