Well, doesn't one need to comb wet hair prior to roller setting, or to prep the hair for any kind of styling? Brushing, of course, is a no-no.
I use a hair pick to detangle my hair. I know that there are fancy detangling combs, but I found that they don't do the job as effectively for me as a hair pick.
In terms of method, there is something called tapping the hair. This is when one takes a small section of hair, and begins to comb it from the ends, and you work your way up the section of hair until you reach the roots. Progressively, you can begin to slowly and carefully comb out the section, and eventually the section is completely tangle-free. One should begin with the ends, and work her way up. You should divide the the hair into small sections so as to minimize damage.
I have found that I lose less hair if I am patient, if I am not too tired, and if I have enough time to do my hair the way it deserves to be done. After all, hair when wet is in its most fragile state.
I hope some of what I have said is useful to you.
northernbelle