Let Go

Far too many exercisers hold on to the cardio equipment their using. Holding onto the machine is certainly good to do when changing speed or resistance, but let go whenever possible. By holding onto the supports, you minimize the efficacy of your workout by reducing how many muscles can be in action. You're essentially resting part of your body (at least a little bit) by holding on.

This is especially true on stair climbers or treadmills at a high incline. If you slow down or decrease your incline, and don't hold on, you'll get a much better workout and get fitter faster!

SuperSet

To get over a plateau or to just change things up in the weight-room, try a SuperSet. Instead of resting in-between each set of your work-out, perform your repetitions for the set of one lift then move straightaway into the repetitions of another lift. The two most common ways to perform this is by either working the same muscle group back-to-back or by working opposing groups back-to-back. E.g. perform a set of bench press, then move right into a pec fly or to a bench press and move right into a row.

Better Balanced Dumbbells

When grasping a dumbbell, instead of holding right in the middle of the bar, place the little finger side of the hand nearer to the weight than the index finger side. This will create a more natural position and better balance for the dumbbell.