How does one play Hecraim "Well"

I've been playing for over a year and a half if not longer, and ever since Hecraim came out I've never been able to play him decently. I've watched games where diamond players will use him, but even they don't do well with him.

I know your suppose to build TF first and then Black Cleaver but it just feels like he does no damage and the only thing he is good for is initiating team fights from what I've seen, aside from being really fast and catching up to people.

I just wish he did more damage