On the defensive side of things, Harlan was a shortstop at first until he transitioned at 15-16. He said that he "grew out of it", so he moved to 3B.
This is part of the reason we see him struggle defensively, but it's something he has worked on a lot throughout the season.
Aside from working with Chase Utley during ST, Chase Harlan said he also worked on lifting the ball more. This is something that Ching-Hsien Ko mentioned in his interview last October, and he has seen an increase in home run production.
Easton Shelton did the same, I'm assuming?