Oh! I forgot to add:

When we hand feed her the mustard greens, we put some in her bowl, pet her [start on your beardie's back, Isis was very very scared when we first tried to reach for her head and it basically got us two steps back, until we petted her back for a while and then worked up to her head], hand fed her, and put more in her bowl, petted her, then hand feed her. Repeat til his bowl is full. He will probably flinch, maybe run to the other side of the tank, but eventually he'll associate being petted with the good thing of getting food. After a while, back off a bit and pet him when you're not giving them food, and don't pet him when giving him food and basically mix it up after a while of petting with feeding, so it's not every single time that he'll expect food.

Also, are you giving him weekly baths? Our beardie has definitely warmed up to us since we started giving her baths. She looooooves the water. she also started to like getting misted sometimes. She rarely touches her water bowl now, except of course when she poops in it... I think it's her favorite place to poo...