Constant tension should be applied to the last five reps of every working set, meaning, do the first 5-6 reps normal tempo, and the last few reps should be held for at least two seconds at the peak of the contraction. This allows your muscles to have more time under tension, and you work different muscle fibers.
Everybody that wants to work out wants to feel good and look better, but I think one of the biggest problems people have is they don't want to work out with a personal trainer, someone like myself, or even a couple of buddies, because they think, 'Gosh, if I work out too hard, I'm not going to be able to get up the next day!'