Heavy incline barbell presses are a well-known chest-builder, but they can be dangerous if you are training alone. Done in the Smith machine, they will hit your upper pecs through a full range of motion with less risk of injury. You can work in some partials to train weaker parts of the movement. Finish off with a set of incline presses with a huge drop set, removing plates and getting right back under the bar each time you hit failure. This technique flushes the muscle with blood and takes you well past failure. Partials and drops on the incline Smith should help your chest a great deal.
Legs seem like the hardest bodypart to use intensity techniques on. Besides the leg extension what can I do to push my legs to new growth?
Legs are enough of a killer without making your workout harder. Partials are a great technique to use with legs. You can do partial reps on the leg press or with squats in the Smith machine or squat rack. Another good exercise would be partial lunges. Pick a heavier weight than you would normally use, and descend only halfway through each rep.
Partials, where you work through only a portion of a particular movement, are very valuable to bodybuilders because they help you overcome weaknesses on certain exercises. If you are benching, for example, and you are unable to do a complete rep with a heavy load, this inability may be due to weaker triceps. Most athletes have trouble with the bench between the halfway point and lockout at the top of the rep, and training in a power rack or Smith machine lets you start at that sticking point without having to worry about the bar falling on your chest. You can therefore make the toughest part of the movement much easier by training to overcome it without risking injury.