Well, memorization is a good idea, as paris suggests, but of course that doesn't *always* happen. So, I will give my suggestion based on exactly what is being asked.
There are a few reasons that I would recommend keeping otherwise loose pages of music in a clean, black, thin (as possible)
three-ring binder. One reason is that if a wind shuffles through the hall, your sheets won't be at risk of falling off the rack. Another is that you can organize the pages to be in order and they will stay in that order. If pages are in a three-ring binder, you don't risk them being thrown off the rack in a way that shuffles your other pages, too.
If you are in a concert and need pages turned, get a
page turner 
. I have been a page turner for a lot of concerts, even some fairly famous people giving solo recitals ! So, there is no shame in it if that's what you need to do. The point is to get it so that the paper is as out of your thought as much as possible so that you can concentrate on the music and the performance.
Hope that helps !
m1469
