The first thing I'd suggest you check is to make sure the gun fits your hand properly. Can you hold the gun such that the barrel lines up with your forearm while placing your index finger on the trigger properly, or do you have to cant it to one side or the other? Different grips may help if gun-to-hand fit is an issue.
If the gun fits properly, then another thing to try is to pay attention to how you're placing your finger on the trigger, especially if you're shooting double-action. I hope I explain this right. I use the distal joint of my index finger to pull the trigger. However, some people will put this joint on the trigger but are actually pulling with their finger tip. This creates an arc motion that can pull your shots to the right. Use the distal joint but visualize yourself pulling it straight back from the distal joint, not from the finger tip, as you pull the trigger.
For me it also helps to visualize applying front-to-back pressure with my shooting hand. By this I mean think of your middle, ring, and little fingers pressing straight back on the front of the grip while the heel of your palm is pressing forward on the back strap. Think of it like a C-clamp. If you're shooting with two hands then visualize the same thing with your support hand, but applying pressure side-to-side. You end up with a circle of pressure around the grip which keeps it stable, yet the front-to-back pressure of your shooting hand helps you pull the trigger straight back.
The best way to practice this is through dry-fire practice. Once you can consistently pull the trigger straight back, and release it straight forward, without disturbing the sights too much (a little wobble is OK as long as the front sight stays within the rear notch), then try it with live fire at the range. At the range you can do ball-and-dummy drills where you mix live ammo and either dummy rounds or empty cases in the cylinder and concentrate on sight alignment and trigger pull. This will help ID any other issues that may be happening, like flinching or anticipation, when you shoot.
Of course, this is just my opinion. There are a lot of ideas on how best to shoot a DA revolver. Research them, try them out, and see what works best for you. I will say that Grant Cunningham's book has an excellent chapter on DA trigger control. You can also check out his website for articles and blog posts for ideas.
