This information will help you to increase your exercise intensity. Increasing intensity makes you stronger as well as bigger since you will keep your body guessing and growing all of the time. There are several simple ways to increase exercise intensity.

One way is just taking less time with the workouts. Simply taking 30 seconds in between the sets as opposed to 1 minute will dramatically make the workout more intense. Another way is to time your workout and do more exercises in the same amount of time you were exercising before. This will also increase workout intensity. The second main way to increase intensity is by simply doing more weight during a workout with a given exercise. More weight means more intensity.Here are more advanced training principles:

Supersets

Supersets are two or more exercises performed in a row without stopping.  For extra intensity, you can even do three exercises without stopping known as tri-sets.  It takes a while to build up the endurance necessary to do a lot of supersets. You can use supersets to train two different body parts - Bench Presses combined with Chins. You will be surprised how a muscle which seems to be totally fatigued will still have a lot of strength remaining if you demand that it perform a slightly different movement.  To do this, however, you need to start with the most difficult movement, with each succeeding exercise slightly less demanding-Bent-Over Rows, Seated Cable Rows, and One-Arm Rows are a good combination. Use supersets to train opposite body parts simultaneously-chest and back, for example.  This gives you a tremendous pump as you perform the alternating pushing and pulling movements, yet gives each muscle group involved the minimum chance to rest and recuperate. 

Drop Sets/Strip Sets

When you are into bodybuilding training it becomes obvious that when you come to the end of a set and seemingly cannot do another repetition, that doesn't necessarily mean the muscles involved are totally fatigued, only that they are too tired to lift that amount of weight.  If a plate or two is removed, you can do more repetitions.  Take another plate off, and you can keep going even longer.  Each time you do this, you are forcing the muscles to recruit more muscle fiber.  This training principle is called the Stripping Method. Do not use the Stripping Method at the beginning of an exercise when you are fresh and strong, but only for your last set.  Since the changes in weight must be made quickly so that the muscles don't have time to recuperate, it helps to have a workout partner ready to slip plates off the bar or move the pin in a machine weight stack.

Drop sets are another way to shock the body.  It involves doing an exercise with say a set of dumbbells, putting them down, picking up the next lighter weight, and doing another set without stopping.  This is actually a dumbbell variation of the Stripping Method.  There are a number of ways of varying this technique; for example, using the dumbbells on a rest/pause basis-doing the exercise until exhausted, putting down the weights for ten seconds, then forcing out additional reps-or working your way up the rack as high as you can, then back down, doing fewer reps with the heavier weights and more reps with the lighter ones.  Another good exercise to use drop sets on is the leg extension machine.  I sometimes do triple drop sets on this exercise.  I would start by doing a set of 10 on leg extensions with 130 lbs. then immediately drop the weight to 110 lbs. and do another set of 10 then immediately drop the weight to 90 lbs. and rep out as many as I can. 

Isotension/Flexing

During your one-minute rest period between sets, don't just sit around watching your training partner do a set.  Continue to flex and contract the muscles you are training.  This not only keeps them pumped and ready for more action, but is in itself a very beneficial kind of exercise.  Flexing is a form of isometric exercise, and isometrics  involve very intense muscle contractions.  Bodybuilders who are posing, flexing, watching himself in the mirror, are not doing so out of vanity.  They are engaged in a very important part of the workout.  You get the same kind of benefits from really hard sessions of posing. The purpose of this stretch is to stretch the skin as to allow more room for muscle growth.  It also keeps the muscles warm in between sets.  This is a great way to achieve some new growth if you are stuck on a plateau for a while.