Next, for any live performance, consider this. When you perform live you are communicating in 2 media, aural AND guess what - visual. You're all focused on sounding great and all the difficulties of your piece and practicing and fixing mistakes, and you look like a dead fish up on stage. Your visual message must match your aural message, the sounds coming from you. You can't look scared or expressionless and have a great impact on your listeners. There are many styles of stage performance: sincere, involved, stage maniac, but they all have in common the fact that they are convincing. You must convince your audience you believe in your music. If you're not comfortable with this visual aspect, it's perfectly fine to "practice" it like you would any other part of your music. Think about your favorite performers, what do they do on stage? Pick some of those things and try doing them, you can even devote several performances a day in your practice to focusing on the visual performance. You're trying to make your live performance succeed 2 ways: if we could only hear you (as in listening on the radio) we'd buy your album. If we could only see you, we'd want to buy the album too, because you look so convincing, it must be awesome music!
When working a difficult piece, start practice some in the middle or the last page. Skip around so you know the piece equally to the end.