You can practise casting Curse of the Bogies.
To learn additional spells, challenge other students to a Wizard's Duel and earn points for your house, you need to have completed the following steps:
•Go to the Great Hall to be Sorted into one of the four Hogwarts houses
•Go to Flourish & Blotts and buy The Standard Book of Spells (Grade 1) and The Dark Forces: A Guide to Self-Protection