while i understand what you mean, keep in mind magick has no colour only intent. the energy in neutral until we cast the spell, the intent of the caster makes it positive [white] or negative [black] depending on the spell cast. as well, magick take more thought than just 'healing is good, curses are bad'. for example, your friend is sick but hates witchcraft. you want to make them better, and know a great spell that will help. you cast it, because you want to help. good, but your friend doesn't want you casting spells on then, which means you forced your will over them, making it bad. so think before you cast.
if i were you i'd start with meditation, and slowly work your way to spell casting. gather basic knowledge like charging/grounding energy, basic herbs, colour association, and circle casting before trying a spell. walk before you can run. good luck finding a teacher, i don't know of many people who take on students.