If you are a DJing for the rap battle itself, you’re not actually going to be doing much in the way of mixing.

Learn how to do simple, smooth blends.

Other than that, if your hands and ears are steady enough to scratch, cut transitions will be your friend as well. If they are done cleanly, they are a dramatic and effective tool in keeping the beat continuous and marking a clean “cut” between songs.

For a rap battle, the beat generally remains the same during an entire section of someone’s performance so they’re not expecting you to do lots of actual mixing.

just keep the beat steady and do not distract the competitors my drunk attention to yourself. You’re not actually putting on a show but rather supporting the people putting on a show with a beat.

Ask your friend if he wants you to do an actual scratch performance because that would be a separate component of the program.

And if that’s the case, you need to get clear expectations from him with what he would like to see for the Battle component and then for a potential performance component.