I have pretty bad stage fright too. I manage it by imagining / simulating the stage situation in my mind when I practice. I only do this after I've got the techniques down.
So stuff I think about when I do my simulated performance:
1. The walk-in, and imagine being a nervous wreck.
2. Not thinking about the music. Which simulates a blank out.
3. After starting to play, start looking around the stage and the audience.
4. Think of all the self-conscious thoughts I would have. And sometimes randomly imagine someone shouting or suddenly an plane crashing in (the latter was described by my guitar lecturer: "If a plane crash into the hall will you still be able to keep playing???" ...haha...)
If you can keep playing and not stop, then you'll realize that you're more free to groove to the music. That's when you can start practicing the moves you like to show in front of the mirror while you do your simulation.
p.s. Not everyone is a nervous wreck like me, judging from your descriptions you have far more concentration then I have. So you may want to go light on the simulation part.