In magic colors often are associated with certain aspects or qualities which can be utilized in spells and rituals. Green can represent fertility, wealth, and luck. Red could represent love, passion, and protection, etc.
Some other things that you might wish to work on, if you haven't done so already, are basic energy work and lunar timing. However, the basic principles and concepts of magic are up to you as to what you actually study and utilize.
If you have the time I would recommend reading the following books:
The Witch Book: The Encyclopedia of Witchcraft, Wicca, and Neo-Paganism. - Written by Raymond Buckland.
Herb Magic for Beginners: Down-to-Earth Enchantments ~ Written by Ellen Dugan
Wicca: A Guide for the Solitary Practitioner. ~ Written by Scott Cunningham.
Living Wicca: A Further Guide for the Solitary Practitioner ~ Written by Scott Cunningham.
They have information on the basics of magic, the sabbats, esbats, etc.