A true story:
Well over 35 years ago, we purchased our very first parrot (I know, BAD!!) from a pet store.
Cleo was a Greater Sulfur Crested Cockatoo, wild caught. A nervous, frightened parrot.
In those days, there was no one to ask, no Internet, only books from the library.
We left her massive cage door open....
We made a simple stand and kept it in the living room, which was across a hallway and across a room away from her cage.
I spent countless hours talking to her...plunked in a chair, next to Cleo's cage.
Not once did I attempt to touch her, or handle her.
Fast forward, about 8 months....
We were in the living room watching TV.
The sounds of pitter-patter, little feet....and there was Cleo; she casually climbed up to the top of the stand we had made for her, ate 1/2 grape from my hand - and the rest was history!!!
Cleo was a lovely, very quiet, very affectionate Cockatoo.
We simply let her observe, and when she was ready, her curiosity got the best of her.
There was no 'taming or training' involved.
Just my spin on things - patience is key!!