[Buzzcook]

http://www.corneredcat.com/Trying_On_a_Handgun/

Okay, gun's empty. Now, with the gun pointed in a safe direction which includes a safe backstop, put the crease of your trigger finger on the shooting-hand side of the trigger face. Do not simply place the tip or the pad of your trigger finger on the trigger. Use the crease.2

With your finger's crease thus on the trigger and without pulling the trigger back, wrap the rest of your hand around the gun to get a good, one-handed firing grip.

A Perfect Fit

With the crease of your finger on the trigger, if the gun's backstrap is firmly centered in the web of your hand, midway between your thumb and forefinger, then the gun fits your hand perfectly. Notice how a correctly-sized gun lines up perfectly with the bones in your forearm. The recoil will go directly into the web of the hand and be transferred along the long bones of the arm, allowing a strong and natural grip without much strain.

Pictures and arrows at the Cornered Cat.