Welcome to the site!
To help you get started, here are some good links to check out:
Tips for Casting Spells
Members here also suggest you learn "the basics". This includes things such as shielding, grounding and centering, circle casting, meditation, etc. If you type "the basics" into the search bar in the right hand corner you will find several related forum threads and articles that you can browse through. Here is another link to help you out:
Best of luck :)