How can I fix my point for ballet?

Good for you! I'm sure you are ready to be en pointe because obviously you seem to be concerned about working very hard! Anyways, do plenty of plies and releves and roll throughs to help build strength in your ankles, which will actually help your arch. Also, to help with the pointing aspect, and also with the arches and strength is to take a theraband and wrap it around your foot. Then slowly point and flex your foot, varying the amount of tension you have on the band. Hope I helped! Good luck! :)