first things first, max out Heimer. i believe becuz he is a natural pusher he should just add to the momentum; give him more attack power.
secondly, make sure your position is yours; a pusher is nothing if he is not able to hold position. in return use his abilities to "mind the gap".
finally, what makes any character good is the ability to adapt to any situation; thus, items are the only thing that completely turn the game from winning to losing.
its all about speed, if u have speed u can have position, if u have position u can manipulate the entire game.