How to concentrate during conference talks where the quality of the presentation is poor? I have read a lot of tips on how to give a good conference talk: know your audience, give context, don't talk too fast, give your talk a clear structure or story, minimize text on slides, etc.

However, more often than not, presentations I've been to break most of these tips (quickly flipping through walls of text and equations while droning on in monotone), and I find it very difficult to concentrate on the talks.  

Any tips on how to pay better attention and be able to learn something from these types of presentations?
When I attend talks where the quality of the presentation is poor, I like to use it as an opportunity to learn about what not to do in a presentation.

I have an ongoing list of "things not to do in a presentation", with examples from talks I've attended. I just take out the list and add to it whenever I attend one of these presentations. I find it helpful for improving the quality of my own presentations - more helpful than just reading tips others have written about presenting, because when I refer to my list I am reminded of exactly why and how a presentation is made worse by [insert bad thing here], from personal experience.

Usually as a result of taking notes on the presentation technique, I end up also paying attention to the content of the presentation, which is a nice side benefit.

P.S. I also have a list of "effective presentation techniques" and I add to it whenever I attend a talk where the quality of presentation is very good.