The Root Of Many Evils
Invariably, when I find myself hitting a lot of bad shots, the root cause is ball position. Let's say I've had a day when I've pushed a lot of shots to the right. Usually, that means I've let the ball slip too far back in my stance, with the result that my hips and shoulders have rotated a few degrees closed at address. This causes me to hit into the ball slightly more from the inside than usual, resulting in shots that launch to the right of my target.
After a day like that, the first item on my agenda on the practice tee will be to check my ball position. I'll begin by over-compensating - playing the ball way forward, up off my left toe. This will open my stance and cause me to hit the ball from outside to in, producing a bunch of pulled shots and slices. Gradually, I'll move the ball back in my stance, perhaps a half ball back at a time, until the pulls and slices stop and I get a series of straight shots.
If you're serious about playing good golf consistently, I recommend that you consider this type of post-round diagnosis and practice-tee cure, with ball position as your first priority. Once you find the position you like, take careful note of it and make it the first thing you check at address when you play your next round.