Don't worry about how much the guy on the bench next to you is lifting. There will always be someone bigger, stronger, faster-always. Your goal may be that 1st place finish and best overall lifter award, but you're really competing against yourself. You want to continue to beat your own personal records, continuously grow stronger, and pass key milestones and personal records.
Don't attempt to lift more weight than you can complete with controlled, proper form. If you're maxing out at 300 lbs, don't try 350. It is sometimes effective to push just beyond your limit, try out that next weight and get your body used to the feel, try 320 lbs. Use a spotter you trust, and keep your form strict. You're not going to continue to improve as greatly from reps completed with poor form-bouncing the weight off your chest, partial squats, etc. You're not going to improve at all when you're injured and are out of the gym for a couple weeks. If (I should say when) you do find yourself under a weight that you are unable to lift, continue to lift with proper form. Rely on your spotter to provide the assistance you need to complete the lift.
In place of the ego set, I do like to add a bonus set. I will add an extra set to my workout with moderately more weight than I've been working with, pushing just beyond my limit. It helps me prepare for what that next level feels like, prepares my body for the heavier weight. If you do add the “bonus set”:
Use a Spotter You Know and Trust
- Don't cheat on your technique to get more weight
- When your strength fails, rely on your spotter for assistance, but maintain form and control
The Competition Lifts
When training for competition, train exactly like you're going to compete. Don't assume you are going to cheat on your form in training (i.e. bouncing the bar off your chest on the bench, performing partial squats, etc.) and then try to clean it up in the competition. Every set, every rep from your first warm-up to your final working set should be performed in competition form. If you are unable to control the weight with proper lifting technique for your target repetition range, reduce the weight. When you lift to failure, continue to lift with control and proper form, rely on your spotter to assist with the completion of your rep.
Love them or hate them, the squat is the anchor of your strength training program. When your squat strength goes up, all of your lifts are likely to follow. Don't make excuses, hit them, and hit them hard. There is no exercise that will improve your overall strength as much as the squat.

Sit into your squats, as if you were sitting into a chair. Your descent should be quick, but controlled. Descend until your thigh is parallel to the floor, and then drive it back up. Keep your head and chest up throughout the lift to prevent leaning too far forward, and force your legs to drive the weight up. Common mistakes are to lean forward too far on the descent and to kick the buttocks out when coming back up. This leaves the work on your lower back to bring your body back erect.

The bench press is everyone's favorite isn't it? When someone sees your large frame and asks “How much can you lift?” they are really asking how much you can bench press. Everyone admires the bench press because of the big chest, the big upper body, right?
I had been strength training for 15 years before I fully understood the mechanics and started performing my bench press properly. With proper technique, I realized the pectorals are more or less just along for the ride, the lats and triceps are where the real work gets done. A few tweaks to my form and my bench press exploded!

As with all your competition lifts maintain control throughout each repetition. Unrack the bar and pause with it locked out and under your firm control. Bring the bar down quickly but controlled until it rests on your chest. The bar should come to a complete stop before pressing it back up. In competition, rules for your federation may require you to wait for the judge's “press” command before lifting the weight. When pressing the bar, thrust it off your chest with your lats. About a third of the way up your triceps will kick in locking the bar out. Throughout the lift, your shoulders should remain firmly against the bench; concentrate on squeezing your shoulder blades together. Your feet, head, and buttocks should remain in contact with the bench or the floor, and should not shift during the lift.