Before casting spells it's important to have a safe space where you feel protected from any dangerous energies.  If your background is Christian a church could be what feels right for you.  If you live in the country it could be a remote clearing in the woods.  Personally, I like to cast a circle, which can be done almost anywhere. That way I have defined an area in my psyche that's separate from everyday space and protected by spiritual guardians I invite from the four directions  North, South, East, and West. A great nondenominational intro series to spell work is Ariel Gatoga's "A Witch's Primer" in Itunes.