It’s prob easier to do this with a video, but I wanna give a short summary on what I know. Before I do though, I really recommend showing me what mouse you have, so I can have a better idea of what you are working with.
First off, let’s talk about Grip and Control. When you aim and move your mouse, you typically have two of three points of Control, your Fingers, Wrist, and Arm. Depending on your sens, you may use Fingers and Wrist, or Wrist and Arm. Usually never all 3 because it’s harder to control and be consistent with. Based on that is what determines your ideal sens and grip.
If you aim with your Wrist and Arm, Palm with a lower sens is great. If it’s your fingers and wrist, Fingertip with a higher sens. Otherwise you could always just Claw till you find a sens that works for you.
As far as finding your sens goes, it really comes down to how you want to aim. You have two types of fast sweeping motions, a Flick, and a Swipe. A Flick is a quick movement with just your wrist, a Swipe is with your arm. If you want to flick, and do a 180 degree turn, or be able to look behind you, a higher sens is what you want. If you want to do a 90 degree turn and look to your left or right, then a lower sens will do.
The best way to find your sens is by feel, and then settle on something for a while until you feel ready to take it to the next step. Or look up the PSA method.
My method of finding my sens is more unorthodox, I basically just used the in game fov, and the width of my hand or grip, got to a good spot, then slowly turned it down from there as needed. Prob won’t work for most people.