This video is a summary of how the first year with our Cockatiel Mojo was like. You will see the struggles and gains I had with my cockatiel. Hopefully it will give an impression of how to teach certain things and that it takes a lot of practice and time. But even with a very anxious/frightened bird like mine, you can still make a lot of progress and get him tame.
Note: every bird learns at its own pace. Your cockatiel might learn some things faster and other things might take more time. Just make sure you get a connection with him/her and be patient.