The first thing that I started doing is cutting the time in between sets in half. Usually I would take anywhere from 60 seconds to 90 seconds after a tough set. I now take around 30 seconds or just count to 1015 (1001,1002,1003, 1004...) that also works great. Now I know what you are saying "how can you lift the same amount of weight a few seconds later?" Well here is how I dealt with that problem. I would do a set of say dumbbell bench presses. I would use the 100 and get say 10 on my forth-set wait 30 seconds and then get maybe 6 or 8. I sat there wondering how a weight that I just got 10 times and now I only get it 7 times. The week before I was doing the 120's 6 times after a 90 second broken. Getting the 100's only 6 times on my last set is a good thing because I know my muscle have hit failure. The next time I hit chest I will try to get the 100's 8 times this way I know I am getting stronger.
This little decrease in rest time will make your workouts go by faster and if you are like me and love to train this is not a good thing. If you look at the positive side of that is that you will get more rest time out of the gym. You will not be able to throw around the weight that you could before but just remember that you are training your muscles to the max and can not even push out another rep.
Another thing that you can try in order to get the most out of a set is once you have reached failure is to rack the weight or put the weight down and then rest for a count of 1001 1002 and then pick it up and pump out two more reps. Put the weight down and then repeat. I would not recommend doing this after every set, but only after the last set or two. You should also make sure that you have a training partner or spotter near by when performing these rest/ pause sets. I perform these on such set as incline bench and leg extensions are my favorite exercises to perform them on.
These are just a few things that can help you break through plateaus and make your workouts a little more fun. Lets face it doing a few easy sets of bench is not going to get you a chest like Arnold and doing a few sets of light squats will not give you amazing quads like Platz. You need intensity in order to become a freak and you must train like a warrior.