Observe the speaker carefully in order to analyse why it is a poor seminar so that you don't repeat the same mistakes. Perhaps if the audience at conferences were more observant in this way then the standard of communication would increase dramatically, encouraging more to attend even if they are not among the speakers. O.K. there are problems with last minute slides, but colour output should be normal nowadays - at least in a computing centre. Wobble wobble wobble. You just get to read something interesting skating off the top left corner when they whip the whole lot off and wobble another slide into view.
Screen is below the level of the front desk and nobody can read it.
When I started in teaching, I was sent on a training course for new lecturers. Needless to say, they were projected onto her body, not the screen. I'm fed up trying to read bits of info. Starting in this way is very negative. Plunge in confidently instead.