Like has already been said, short game. I chip in the yard and putt in the house almost daily and it's paid off. I still suffer bad tee shots, thin iron shots etc....but once I get within wedge distance, I have confidence in that game now.
I started with putting in the house. It's the most used club in my bag and easy to do. I just focused on building my swing, what felt comfortable for me.
Then I moved to my chipping. I have a bucket and I chip into it ( or at least try :) )
Once I get within wedge range I know I can do what I need to, whether it is a pitch or chip on.
With my wedge game, I've worked on shortening up my club by choking down for control. I also had my putter cut down ( I'm only 5'4" )
Right now the biggest change I have made is with my general grip. I've found a setup system with it that works well for me. I call it my 1-2-3 setup because as I grip the club I identify and focus the three areas I want to feel in my hands ( finger pads of first 3 fingers on left hand, pad of right hand where it lays against left hand and index finger of right hand )
Once I set these up and remain counscious of how they feel, I get better control. My shots are generally on my line now, with my only problem being coming up short or going to far.