In my opinion a golfer can block their drives in any of 1 of the following 4 ways or some combination of the following 4 ways.
1. Heel Strike
2. Open Face to Path
3. Right Club Path
4. Hit down on it- (combo with 1-3)
This is too hard to diagnose on your own so go see an instructor with a Trackman. If you are set on trying to fix this on your own do the following.
1. Spray the face with foot spray so you can tell if you are heeling it.
2. Strengthen Grip to help close the face.
3. Swing outside in
4. Stay behind the ball and try to hit up on it.
If you try those four things you might be able to see what was causing the issue in the first place and then focus on that.