I don't claim to have a cure-all for shanks, but when I get them I have a fix.

When I shank the ball, it seems to be because my body is active and my hands/arms get lazy. I get rid of them quick with the swing thought of accelerating my arms and releasing the toe of the club. Releasing the toe of the club should also help your slice.

Breaking 80 is going to depend a lot on your iron play. Hitting your woods and hybrids good is obviously going to help, but your iron play and short game are where the emphasis should be. Once your ballstriking is fixed, concentrate on course management and get in the habit of developing a quick hole strategy when your on your way to the tee box. Course management can make the difference between a day of bogey golf and a score in the upper 70's, of that I am sure.