limitations. Even if you made incremental strength gains during every single workout, you'd eventually bench press over 1,000 pounds.
The best way to break through a plateau is to make some sort of change to keep your body guessing. Trying different exercises or machines or changing the amount of reps you usually do can certainly help. Resting more should also help if you're overtraining, as well as resting less if you're undertraining, though you should avoid overtraining at all costs.
One very intense weight training workout that may help you break through a plateau is the 10 sets of 10 workout. This workout is not 10 all out, lift to failure sets of 10 reps. Whatyou do is take a weight you can do 20 reps with and try to do 10 sets of 10 reps with 1 minute of rest in between each set. If you can bench press 135 lbs. 20 times, you would take that 135 lbs. and do 10 sets of 10 reps with it. The first few sets will be easy, but once you get to the 7th and 8th sets your muscles will be on fire. By the last couple sets you may very well not get all 10 reps. If you try this weight training workout don't do any more work on that bodypart that day, those 10 sets will be more than enough to do the job. This workout will leave you extremely sore for a couple of days, so make sure to get plenty of rest before you work that bodypart again. Here's a sample routine:
Day 1 - Chest and Back: Bench Press or Incline Press 10 X 10
Cable Pulldowns or Rows 10 X10
Day 2 - Rest
Day 3 - Arms: Dumbbell or Military Press 10 X10
Barbell or Dumbbell Curls 10 X 10
Lying Tricep Extensions 10 X 10
Day 4 - Rest
Day 5 - Legs: Squat or Leg Press 10 X 10
Standing or Seated Calf Raises 10 X 10
Day 6 - Rest
If you want to do deadlifts in this routine you'd be best off if you did them on back day as your upper back will be as sore as your lower back after doing them. Try this weight training routine for 4-6 weeks before going back to your normal routine as you'll want to get back to doing more exercises. It should give you the kick you need to gain more size and strength.
Another suggestion to help break through a plateau would be to do some drop sets at the end of your weight training workouts. When you get to failure on a set quickly drop the weight by 20% and rep out with it, then drop the weight 20% again and rep out again. If you do this at the beginning of a weight training workout, you may be too taxed to effectively do the rest of your routine, so just use drop sets as finishers.
Changing the amount of reps you do regularly will also give your body the change it may need to break through a plateau. Try doing a light, medium, heavy routine. On your light day do 12-15 or 15-20 reps on all your sets, on your medium day do 8-12 or 10-15 reps, and on your heavy day do 3-7 or 5-10 reps. Experiment with your rep ranges to see what works best for you.
Plateaus can be tough to deal with, but making a few changes should allow you to break through them and start gaining strength and size again.