I don’t think we should get too hung up on how we look when we give a presentation so I urge you to read these body language interpretations to make yourself aware of them, but I wouldn’t read too much into them.  The most important thing is for you to be you, not someone else’s interpretation of what you should and shouldn’t look like.  And by the way, although most of these are widely accepted interpretations, I present them as my personal opinion.  If you have other interpretations, I’d love to hear them.