You know something, my Marley won't come onto my hand from his cage. He's 2 years old now and loves me to death, he'll come onto my shoulder or hand off the bed during free range, but when I'm trying to get him out of the cage its almost like he doesn't want to. I STILL don't get it. I'll use a treat and he'll just stretch as far as he can without getting all his paws out. I usually either work with him for 7 minutes before he gets the picture, go on in and scoop him out (which I try not to do, I want him to come out on his own accord), or use something else as a bridge to get him from the cage and onto my shoulder, like a piece of tile.
So it could be that he's just weird about stepping out of his cage. But I would definitely check out the immersion sticky from Rat Daddy. Other than the immersion, what I would do when my boys were young to get them more friendly was put water on my hands, and show it to them. They would lick the water off, and even when it was all gone they'd still be licking to be sure they got it all. Or apple juice if they weren't interested in the water. Yogurt I've tried--at first they would think it was something to grab on to, and would get my finger but after a few moments of confusion they'd start licking. I also recommend you invest in a bottle of Gerber Puffs. Little star shaped puff things of different varying flavors (dont get sweet potato, rats can't have them). There's nothing to these treats, as far as calories and fat, so they can have a lot before they've had "too many". I associated a sound to the giving of a treat, so every time I had a morsel for them I'd make that sound and they'd learn it meant I had something for them.
I've also heard a few people that wear hoodies with those long front pockets, and put the rat in that pocket and just walk around with it. I know Marley loves to snuggle in my hoodie pocket now, but as a new rat it would be a place to hide, near his new mommy, while I introduced him to the smells and sounds of the house.
Jess <3 mentioned at the end that she's never felt as close to them as she does now; what got me to this point, personally, was really thoroughly understanding that these are thinking, emotional creatures. I handed Marley a kleenex to stuff his house with and he gets super excited about these, so he grabbed it really quick and accidentally nipped my finger. It hurt, so I made that hiss noise when you get hurt surprisedly, and examined it. He'd run about halfway to his house by then, but stopped and set the kleenex down to come back to me and give my hand a few quick kisses before turning again to finish his house-stuffing. He realized he hurt me, felt bad, and came back to apologize. Once you get to a spot where you can read your rat, listen to it and understand what it's trying to communicate to you, I'm sure it'll be easier to trust train. I didn't really understand that until after we'd already connected, but I'm really pretty sure it'll go the same for you at this point.
best of luck