Get custom fitted for your clubs. I played the last 15 years with some Ping Irons that I thought was ok for me (they are not bad clubs, I thought I was just playing badly), but started hitting them even worse the last couple of months (probably the shafts are done by now). Came out the lie angle, length was never right for me and I couldn't swing naturally and had to adjust myself to fit the clubs, which is never really recommended.
Got custom fitted Irons and actually so far after 2 rounds took 5 shots of my score.

Still strugling a bit with the distances of the clubs though as I hit these much longer. And No Custom fitting didn't cost me anything more than the standard price of the clubs.
With the custom fitting I told them what my budget was and they got clubs in that price range. I hit 6 or 7 different makes and then was left with 2 that I really liked and felt I hit well. One the flight scope this also came out as the clubs I hit the best and then they worked it down from that. Measure your length length of your fingers, swing speed etc etc. Keep in mind not everyone is the same length and hand sizes differ etc, so unfortunately one size does not necessarily fit all.
Now if I can just start hitting the driver in the fairway that would help, although maybe the driver is not right for me either.
Just my 2 cents on my experience on this.