It's that guy behind you. He keeps dipping his nachos in your back. Dilettantism is the mark of an amateur. Avoid needless embarrassment. Practice the correct pronunciation of your deity's name in the privacy of your own room before chanting it in public.
Flash cards are often helpful.
Before agreeing to impregnation by a supernatural being, investigate the survival rate of the other people who have undergone the procedure. Citronella candles may not be used in rituals. I cannot stress this strongly enough. Fluorescent lighting is very annoying to most netherworldly creatures. When the Black Mass goes awry, stay away from the Evil Priest.