After finding the right width, grip the bars or handles firmly and push yourself up. Squeeze your butt and abs while pointing your toes and keeping them slightly forward of the hips. The shoulders should remain back and elbow pits forward at the top of the dip. Avoid crossing the ankles, moving into extension or bending your knees behind you.
Once you establish a good support position, pull your knees up and begin to rock your hips forward without letting you back round or shoulders elevate.