Sight picture - concentrate hard on the FRONT SIGHT ONLY.
Set the front sight from just below the black to the bottom edge of target. Area aim- your preference.
Squeeze the trigger slowly whilst concentrating on the front sight.
Shoot at blank cards or reversed targets, so you don't have to contend with the "distraction bull". You'll be surprised how small and centred your groups become.
Don't just keep shooting, hoping for it to get better; analyse each shot to find where you went wrong (or right!).
Your problems are likely to be 50/50 trigger control (snatching not squeezing) and your eye leaving the front sight.
The INSTANT your eye goes from sight to target, the shot is lost; believe it!!
Edit: Oh and follow through after each shot, holding aim for at least a second or two.
Walther CP-2 Match, FAS 604 & Tau 7 target pistols, Smith & Wesson 6" & 4" co2 pistol, Crosman 1377,
Baikal IZH 53 pistol, Gamo CFX Royal,177, Umarex SA-10 CO2 pistol.