A lot of interesting responses here. I've got a different perspective on the issue.
I believe that once you've developed the physical skills & properties to play this game that its 90% mental from that point forward. I believe that intimidation, pressure, fear are not real tangible things but a creation of your mind as that's the only place they exist because its there that you fabricate them and feed them.
I believe that is no such thing as fear or pressure or intimidation, at least not for myself as I believe that since they are self created by your mind you can also choose to not create them. I stay within myself when I play, no matter the circumstance. I've had others compare me to a robot as I don't really acknowledge my opponent & only focus on what he's doing at the table enough to insure he hasn't committed a foul, other than that he's ignored. Focus on your breathing to flatline heart rate and adrenaline. Instead of giving your opponent attention focus on the table when he's at it making adjustments in your strategy for the table as it changes. Use positive visualization, "seeing" the ball go in the hole and the cue ball traveling the path you desire it to place you in line for your next shot. What you'll find is that if you just focus on your game & have confidence in your abilities then these things you struggle with will vanish. Being detached, playing within yourself & not acknowledging your opponent actually intimidates other players, that's my experience anyway.
Any energy you expend on something you can't control only lessens the amount of energy you can apply to what you can control.
Why am I the Colonel? Because I always get the chicken