It is very important to grip your handgun properly, to help you shoot accurately and minimize recoil. If you are not holding your hands in the proper position you may injure yourself when the slide comes back ( see picture below) or even worse drop the firearm!
Remember- KEEP THAT FINGER OFF THE TRIGGER. This is the proper place to kkep you finger at all times until you have aligned your sites and are ready to shoot.
Here is a great video to watch and visualize a proper grip.