Know yourself. If you have any doubts about the work you intend to accomplish, don't do it. If someone asks you to perform any spellwork for them, consult some form of divination before you do so.
Make sure that the work you perfom is for the good of all involved.
Watch for what the moon phase is at the time. If you want to bind or banish, do the intended work during the waning moon (full moon to new moon). If you want to draw do the intended work during the waxing moon (new moon to full moon).
Above all remember to harm no one, including yourself.