Originally Posted by: schmangeWorst scenerio...if you actually do screw up, try to make it look like you did on purpose

That's good advice. My guitar teacher once told me before my first recital that if I did screw up the song, not to shake my head in disgust or anything like that. Because if you're playing your own songs, no one's gonna know you botched it. And if you're playing someone else's songs, they're just gonna think you're changing it up a bit (and therefore are a musical genius). Crowds are kinda dumb that way, or so I've been told.

I am also reminded of a "Guide to Improvising" I read in Guitar World: If you make a mistake, it's an accident, but if you keep repeating that mistake, it becomes jazz. :)