Oi! Do you do what your friend told you, to wave your wand in an arch, or do what your other friend told you, and wave your wand in a crescent shape? You don't know!! Always make sure that you consult a professor or a textbook before you go ahead and test out a friend's advice. After all, their words aren't always correct! Were your friend's words certified by a book publisher and the Ministry of Magic? Probably not! (Note: always ask if a friend's advice was certified by the magical government!)

Don't be confused by others! For exact information, dive straight into a book! After all, a book is rightful evidence that what you are looking for is the correct information in that book!