The best teacher is yourself! Although a personal teacher would be good. Trying to teach on-line is difficult, if not impossible!
And, if you are trying to cast spells, then you are not studying witchcraft; you are studying Wicca! Although Wicca does use witchcraft, it is really a religion; witchcraft, of itself, is not! It is many,many years ago since witches cast spells! That was when everybody believed in supernatural forces. Many still do; but many do not!