I think the following list of common-sense advice from a self-defined Hedgewitch is worth 5000 laws of magic.
A Reality Check on Magickhttp://walkingthehedge.net/blog/category/grimoire/
Only YOU are responsible if you bungle a spell and harm yourself or others.
Spells that change the color of your hair, change red traffic lights to green, make you invisible and such DO NOT WORK. This is not Hollywood.
Spells that force a person to act or feel against their own free will rarely work, and when they do, they always wear off. There is also a high price to be paid for such spells, so think twice.
If you think you have been cursed or some such thing, chances are you HAVE NOT been cursed, you’re just having a run of bad luck.
Start small and work towards the big stuff.
Use your common sense.
Make sure that any work you do is worth any backlash you may receive.
Choose your words carefully.
Magick is a not cure-all for your life’s problems.
Magick takes a lot of energy out of you; it is not advisable to cast spells while ill or tired.
Energy work, such as working with tarot cards or casting spells, can be very wearing on your natural reserves, try not to over do it.
Bragging about how powerful you are makes you look like a loser.
Never raise something you cannot put down.
Know what you are getting into, do your research.
All the cool looking tools in the world will not make your spells more powerful if you do not know what you are doing.http://walkingthehedge.net/blog/category/grimoire/