Have your palms facing up and use the biceps (no swinging) and keep your elbows tight to your sides to pre-exhaust the arm muscles.
You want to start at about 90 degrees (the sticking point of a curl) and squeeze the dumbbell up to finish, again maintaining strict form with your elbows in. Use a lighter weight if you cannot maintain perfect form.
Use a bench, keeping your body straight, do push-ups with your hands slightly more than shoulder-width apart.
Stand tall and grip the dumbbell with your hands in a diamond position. Bring the weight straight up over your head, keeping the elbows in.
Get into a bent-over row position and use the triceps to push the weights toward your backside. Maintain strict form on this move, locking in your base back and arm position.
Using a bench position your hands comfortably behind you on the bench. Lower your whole body, isolating the triceps, and push straight back up.
Standing Pulley Tricep Extension:
You can grab the pulley rope or small rotating straight bar (pictured) as if you were doing a regular tricep extension facing the machine. Simply rotate away from the machine to face away from it. As you turn, bring the rope or bar up over your head and once you face out, you will be in perfect position. (It’s easier than it sounds.) Lock your base position in with a split stance (for a strong foundation) and isolate the triceps.
Compound exercises are popular, but don't forget isolation moves.