My best advice is patience, and lots of it.
You have to remember chinchillas are prey animals and you are a predator, it will take time for him to trust you. I got a baby in June and he is only just letting me touch him now, and then only for a few seconds at a time, but it's getting longer.
Some tips:
Sit by the cage and talk to him softly. Put your hands near the cage for him to sniff and then through the bars. Chinchillas bite out of fear but if you let him smell you first before you put them in he should be fine. Chinchillas 'taste' with their teeth in the same way that dogs smell something to find out what it is. They just sort of scrape their teeth on you and it doesn't hurt at all. If they do bite a little harder than you would like, make a yelping noise and pull your finger away, that way they know they've hurt you.
Break up a raisin into lots of small bits and feed them through the bars.
Then when he's okay with you being outside the cage open one of the doors and put your hands in palm up. Let him sniff and walk on your hands and arms and feed him a few treats, but not too many or you'll make him ill.
Just talk gently to him and don't make any sudden movements. It probably will take about 6 months for him to trust you but every chinchilla is different. It's so rewarding when they do.
Don't chase him around the cage, or chase him at all if you can help it. When letting him out the best way is to have the cage in a secure room and just open the door to let him come out on his own and then when he goes back in close the door and give him a treat. That doesn't usually work though.
You can make is so he has to come onto your lap to get out, have a quick cuddle and then put him down yourself. That way he will associate playtime with you. Or you can usea carry case to transport him to a playroom. Most people give their chinchillas a treat when they go back into their cage, either on their own or via you.