As I may have mentioned, Ive taught myself to play the intro to sweet child of mine on expert mode blindfolded, there's a trick to learning how to do this, and i'm going to teach you how.
1- don't use a blindfold when your practicing
when you first start practicing this trick, you never want to use a blindfold, just close your eyes. The logic behind this is that if you do lose your timing, you can easily recover, close your eyes again and finish the song
2- know the song by heart
self explanatory, listen to the song over and over again, know every beat
3- relax, and understand its going to take time
understand, that playing a song without your sight is impressive for the simple fact that its hard to do, its going to take practice and your going to miss many a note
4- pick the right song
by which I mean a song with a nice repetitive (but exiting) beat sweet child of mine is a prime example, the only thing that could make it easier to learn is a drum beat in the first part of the intro.
if your not able to nail the part of the song 100% do that first before you start playing blindfolded, the reasoning behind this is if your playing blindfolded, and you miss a note, your going to most likely throw off your timing, fall into a rut and get laughed off the stage.
once you have the technique down, throw on a blindfold and let the awesomeness ensue. If your having trouble convincing people, just play blindfolded and facing away from the tv.
Other tricks I include in my arsenal include playing behind your head (as seen done by Clive in GH1) which is so easy I shouldn't have to explain it, playing "cross" which means I'm strumming with my left hand, and using my right hand to play notes, this is a bit harder, so I only do it on lower difficulties, and lastly there's sitting the guitar on the ground, and playing it like a mini cello or orchestral bass, easy, not really to impressive, but fun none-the-less.
got any tricks to share? or have any comments or questions on the lesson? let me know.