In my experience, what works for one bird may not work for another. My male cockatiel (the one with the social problems) absolutely adores the shredder toy I gave him. It comes as a roll, about an inch wide, of woven palm fronds. You should be able to find something similar in any pet store that sells bird toys/supplies. He is beside himself when his "friend" is not in his cage, and when he spots it outside his cage, he goes ballistic and eventually gets the nerve to fly out and follow it.
In the few months that I've been giving him this particular chew toy, he's destroyed about 6 feet of the stuff.
My female 'tiel on the other hand, could care less about the palm fronds. She had a feather-picking bout when I first got her, and I strung the palm all around her perches to help distract her...which it did. But now, she's not feather-picking, and really hasn't touched the toy.
And, some birds are slow in responding to stimuli like toys. My male at first really didn't like the palm--or anything new or different in his cage. He hissed when I gave him a small bit of corn-on-the-cob (bought from a bird supply store, perfect size for cockatiels). He at first hissed at the palm fronds too; he didn't know what to make of it. But after awhile he got over his fear, and now I have to make sure I always have some at ready hand. (he's also grown acclimated to the once-scary corn on the cob.)
Also, if you haven't already, try a bell toy. Make sure the "chain" or whatever the bell is dangling from is a material safe for 'tiels, and not metal. My male *Loves* ringing his bell, and again...my female has one too, but she doesn't get into it like he does. (Hm, this reminds me to find something new for her. She's been partial to mirrored toys...my male just hisses at his reflection.)
As far as building trust... A clipped bird will be easier to manage out of the cage than an unclipped one. Both of mine are unclipped now, but I kept them both clipped for about 6 months after I got them. I kept my male clipped awhile longer than she because he would literally bite the hand that feeds him, which I didn't blame him...new environment, new people and all. I didn't want him getting up high and out of reach, or me risk getting bit to get him back down to safety. When he depends on you for everything, he should calm down.
I would recommend taking him to someone who knows firsthand about clipping avian wings; I never got to the point I could trust myself enough to clip my own birds' wings. There are websites and books to tell you how to do it, but it's a different creature when you have a squirming bird in one hand, clippers in the other. (*shudder*)
I hope this helps. Remember to be patient, try not to rush things. =) Good luck!