The triceps dips is one of the best exercises you can do to build huge triceps, and it will also work your shoulders and chest. This is a body weight exercise that requires some heightened surface, like a bench or chair.
The bench dip is a compound movement, so besides your triceps, it will also work the shoulders, chest, lats and traps.
It is very versatile exercise, if the bench dips become too easy, move forward to doing the dips with your feet elevated on another bench, or try parallel bar dips.
Keep your shoulders back and down, don't let the shrug or roll forward it will put them in risk of injury.
Keep the elbows pointing backwards, instead of out to the sides, throughout the movement. Your forearms should always be perpendicular to the floor.
If the exercise is too hard, you can bend you knees to reduce the pressure on your muscles.
Don't dip too low, this will put unnecessary stress on your shoulders. Dip until your upper arm is parallel to the floor, and in a 90 degree angle with your forearms.
You can also change the difficulty by adjusting the height of the bench. An higher bench will be easier than lower bench.