Shoot from a rest or offhand, if confident. Set the target at no more than twenty-five yards.
Shoot a ten round group, slow fire. One desires to see how the handgun shoots in relation to the sights. Use a consistent point of aim even if all your shots are a couple feet off. Do not 'hold off'.
If the group is more or less round, you are shooting correctly. If your group is round(ish) but large in diameter, you are shooting correctly, just not as well as you should. More concentration and working will shrink the size of the group. However, if your group is ovate then technique is faulty. One is either flinching, bucking, pushing (with the trigger finger on) the trigger, pulling (with the trigger finger on) the trigger, closing one's eyes and hoping for the best or something else.
If round, adjust the sights. If oblong, get some coaching. Then adjust the sights.