Can not tame my tiel..

SO I am not new to forums it is just that the one i used to ask my questions at was not helping at all. I used to have this fun little friend called riko for 2 years but i was way to busy to be able to spent as much time as i was eariler so i decided to get another tiel. poko. When we arrvied at the petshop to get poko we found him in a cage wit all these diferent kinds of parrots and he looked so scared so we were like hey we will take this fella. But who knew that he is so scared of people that to this day i havent been able to make him feel comfortable around me. yea he will stay on my hand but will try to bite me many times. Then riko decided that it was a good idea to open the cage and leave... so i was left with poko.. for 6 months i was trying to give all me attention to poko in case he decided to understand that i am no enemy. but nothing. sooo i decided to get him a friend pokito. He is only 4 months old but poko is 3 years old. now i do leave them outside the cage together cause they love eachother but what this has led to is pokito being scared of me too cause of poko. I dont know what should i try with poko to make him feel good around me.. I will probably each one in seperate rooms so i can tame both of them seperately.

I found this article to be pretty helpful! Working with Fearful Parrots: A Study in Videos | Learning Parrots

Forgot to mention that i am not new to taming as i did tame succesfully riko and was able to do anything while having him around me outside the cage. Thanks Littleredbeak i will check that out.

Target training is often very helpful.

I will also copy a link in hsve on stress in parrots, talks about patterning to music abd other stuff.

Even when we have experience, its often good to review the basics. I have over 20 years working with or having birds. I'm constantly re exploring and going bsck over info. Here I've picked up great stuff from brand new owners as well as experienced owners. Its a great community.

A few months ago I got a friendly quaker from a pet store, but had a huge fear if hands. It took a lot of work and trust building , postive association to overcome this. And I'm still not all the way there. I layered postive association, by saying good birdie from across the room if he was eating, or playing. Or talking s bath I was always sayinggood birdie to be associating with anythinghe fid thst made him happy, even as he was just falling asleep i'd say good birdie softly as he fell asleep,
https://lafeber.com/pet-birds/stress-reduction-for-parrot-companions/

I hope I get the names right. Train Pokito in front of polo cage. This way Porto will see how you are treating pokito.
Also use millet spray as a treat and when you give pokito a treat see if you can get Porto to take a bite of millet from inside the cage. With Porto you will have to go really slow, not to push him and make him afraid. You need to work with pokito and leave pokto in his cage for now. Just try and get pokto to follow you will the millet spray from inside the cage so he sees that you are a treat machine.