Basically magic covers a broad range of things, some simple and some not so simple. Take the following examples: Divination, the art of using a state of consciousness to learn things which may normally be hidden to you. Healing, the focusing of and/or transfer of your energies for the purpose of healing injury to yourself or another. Spells, ritual acts which really do whatever the caster needs (needs, not wants).

Magic is of course governed by a few laws as to how it behaves. The first, commonly known as the law of three, or the law of return, states that whatever you do, will come back on you as well, and usually magnified a few times. Wiccans extend this law to all things, not just magic, but I've found it particularly true for magical workings. Many other non-Wiccan systems of magic hold this belief about magic as well, so it's not just Wicca. Make sure that when you do something, you realize that you are doing it to yourself too. The next law, Harm None, is pretty much common sense after reading the first. Who wants to curse someone when something 3 times as bad will befall the caster? Admittedly there are times when this line has to be crossed, but be very careful that you have a *damn* good reason for doing so. For example if a mugger is about to shoot someone, even after they co-operated and gave up their wallet. If you protect the victim by making the mugger slip, fall and knock himself out on the sidewalk, you have caused harm, but with good reason to.

Another issue is what exactly is harming someone? clearly physical, psychological, and monetary harm are obviously not acceptable, but there are some things you may not think of at first glance. For example, controlling others, selfish gain, selling magic (cheapens yourself and your craft), and treating others as "toys" are all forms of harm of another. Think first, cast later...