How To Perform The Cable Pallof Press
You want the cable at roughly nipple height. Use a d handle attachment or a nylon plastic handle. Either interlock your fingers or place one set of fingers over the other. Whichever is more comfortable.
Take a couple of steps away from the cable stack and face sideways. The cable itself should be pulling you to the side. Use a slightly wider than shoulder width stance. Don't be hesitant to further widen your stance. The wider your stance, the bigger your base of support and the more weight you will likely be able to use.
Start with your fists up against your chest. Press the cable away from you until your elbows are fully extended. In this extended position you should feel your obliques contract. The further away from your center of gravity the resistance goes, the harder it is on the obliques. This is why it is of the utmost importance that you fully extend your elbows on each rep. That extended position is the most important part of the movement so spend an extra second with your elbows extended. If you start fatiguing to a point you're unable to maintain your torso position, end the set.