Wear a watch. Honestly, that helped me keep going in my last Fran. The timer is what grades you, so time your rest periods with it as well. Commit to a single plan of attack with sets and rest times all predetermined. Let the timer govern your workout.
Probably not something I could have done a month ago, when I was just beginning to use the CF metcons, but it worked great just a while ago, and with better pullup endurance, I think I could go a lot faster!