The basics of working out.

[jamesbowl50]

Start your first exercise with a very light, easy set of ten repetitions. Never warm-up to the point of failure or exhaustion. You will be expending much needed energy if you do, energy that will be needed for the last heavy sets.
Make sure your workouts are under 45 minutes. This is important for several reasons. First, it is easier to focus intensely for 45 minutes than it is an hour or more.