@typhlosion @binary Seconding tarot and meditation; with meditation you don't even have to worry about 'think nothing'; a good start that will get you pretty far is 'observe thoughts, and let them pass'; just try not to get stuck on any specific train of thought.
For witchcraft/paganism more broadly, there are a zillion-and-a-half intro books and blogs and stuff, all pretty interchangeable. Read some, and feel free to mentally bin huge chunks of them as ridiculous nonsense. ;)