Lizard trust issues

[youngster]

I got my beardie in August off a person I know who was going off to college and couldn't keep him.
It became quite obvious to me that he was being kept in sub-adequate conditions but they weren't extremely bad.
The worst part IMO is that it became apparent that they handled him VERY rarely if ever. So, as expected he doesn't really like being handled.

My question is what are the best ways of building trust with him. I try handling him everyday and I do some trust exercises like putting food on my arm and making him climb onto me to get it. And he seems to be getting better but very gradually. Any tips/suggestions are highly appreciated. Thanks