The two main rules for spellcasting are:

The Wiccan Rede states, in effect, that you must not do anything to harm anyone--including yourself. Manipulative magic, doing magic without the object of the spell's knowledge and consent, is considered harm; thereofore, it is outlawed. That includes the "love spells" like were seen in "The Craft".

The Threefold Law:
That Which You Do, Returns To You Threefold.
That means that if you do manipulative magic or curses, it will backfire and hit you instead of your intended victim. And it will hit you three times as bad.

Then, there is a major part of magic:
visualization
Visualization is seeing things, sort of in your mind's eye, but in your field of vision. Try this: Close your eyes. Try very hard to "see" something--an object. Now, when you can "see" that object well in your mind's eye, mentally take that object and begin to turn it around, studying it from every angle. What does it look like? Does it have bumps, spikes, markings? What is its color? When you can hold that image in your mind for five minutes, open your eyes and try to "see" that object somewhere in the room. Continue to mentally study it, seeing it from all sides and noting every detail. When you can do this for five minutes also, you're ready to move on.
Now, if you've gotten all that, you are ready to start the ritual.