I am a newer shooter who has been watching you tube for tips on shooting accurately. Most videos suggest keeping a very tight grip and locking the wrists. I assume that this is to control recoil. When I do that, my hands get a little shaky, making it hard to the sight picture.
Sure! First, I would recommend taking a beginners course with a professional teaching you the proper stances, grips, etc. When gripping your pistol, though, you want a firm grip but not trying to squeeze it to death. Get a tight grip, and if you're shaking then loosen it until you stop shaking. This should help with your sight picture. Also, you do want to maintain stiff wrists with semi-autos b/c if you don't the pistol will very likely stove-pipe or jam in some manner. It's best to find a range and ask the range officer to help you with your grip/stance, etc.
With dry-fire practice I go for the death grip. This trains and strengthens my muscles, it especially trains my trigger finger to be independent. When firing I don't think anywhere near as much about the grip. My muscles already know what to do.
I beg to differ with GCBHM, a little...
One way to teach trigger control, and the isolation of the trigger finger, is to tell the student to grip the gun very tightly...I call it "the death grip."
If the lower fingers are uniformly gripping tightly, separate attention can be paid to trigger-finger control, which is the key to accurate shooting.
It also helps materially with recoil control.
If the pistol shakes in the hands, that's OK. The shake is smaller than you think that it is. At close, beginners' ranges, it won't affect accuracy at all.
The wrists should be locked, of course, but so should the elbows, and even also the shoulders.
All aiming movement should come from the hips, not from the arms.
The idea is to turn the pistol into "the barrel of a rifle." The shooter's arms then become "the rifle's stock."
But, of course, the real accuracy issue is the isolation of the trigger finger. It should move in complete independence from the grip of the rest of the hand.
Create a good, solid sight picture, and place it on the target. Pay attention to keeping the sights aligned on one specific place (not necessarily a bullseye or other mark).
Now, keeping the sights aligned and in place on the target, press (don't "squeeze" or "pull") the trigger straight back until the shot goes off.
I've always been able to maintain isolation of my trigger finger naturally I guess, and I am more comfortable with a firm but not a death grip, per se. My aiming technique differs depending on the type of shooting I'm doing. If I'm shooting at longer distances, I may tend to close one eye to gain a more precise point of reference focusing on my sights rather than the target, the target being the background with my front sight being the primary point of focus. I am able to do this with both eyes open, but sometimes closing the one eye helps me to be more precise. At shorter distances, however, I always keep both eyes open and focus more on the target with the pistol being the secondary focus if that makes sense. It works well for me.