The fundamental requirements to hit a small target with a handgun are simple: Align the front and rear sights; place the properly aligned sights on the target; then press the trigger without disturbing that sight alignment. That's easier said than done.
Handguns tend to wobble, bobble, and bounce. That's the reason why most experienced handgun hunters are enthusiastic tree huggers.
A tree trunk, limb, stump, or fallen log can provide a secure rest to steady your handgun. But there is a pitfall to avoid.
Don't allow any portion of the gun to touch the wood. Placing any gun against a hard object will often cause it to shoot away from that object and spoil the shot.
Snug your hands to the tree to steady the gun while cushioning it from the wood. In other words, hug a tree for better handgun hits in the field.