One of the more helpful things you can do when getting ready for a performance is the video record practice sessions.You don't have to record the whole session. At the end of the session, just record yourself performing the song and then watch it back.
The main thing you want to focus on is how the video makes you feel. Do you want to watch it over and over because you think it's cool? Would you pay top dollar to hear yourself play like that at a big concert hall?