ive recently been spending about 10 to 15 minutes doing a kind of "meditation" right before i go into the gym, meditation is the wrong word bc its kind of the opposite, where instead of calming myself down, i try to pump myself up. makes a big difference in my workouts.
also, i agree with brick, keep it simple. i no longer count sets, or reps, or even days between workouts. i just go in pick 3 or 4 compound movements and try to keep my intensity up. another thing is to not put too much thought into how much you weigh, instead focus on how much you lift.
sorry, guess that was more than one...