How do you get a girl by the end of school if it is tomorrow?

You can't reliably "get" a girl by the end of tomorrow. Building genuine connections takes time. Trying to force something in such a short timeframe will likely be unsuccessful and might even be off-putting.

Instead of focusing on "getting" a girl, focus on being yourself, being respectful, and making genuine connections with people. If you have a crush, tomorrow might be a good opportunity to have a friendly conversation, but don't expect a relationship to develop overnight. A short, friendly interaction is a better strategy than any attempt to "get" someone.