I am sure most of us has ended up with a birdsnest on our spool after a overhead cast. To reduce the chance of this happening, try pointing the rod tip at you iron jig while following through right down to the water, don't forget to stop the spool with your thumb just before the iron hits the water.
I have also learned from some old schoolers that as you throw it out,roll your reel over till the spool is in a vertical position,and the line peels off easier,and like you mentioned."educate that thumb"