here are some simple tricks to teach you tiel and how to teach them
1. summersult
tiels always do summersults in the wild. get your tiel on you finger and wait till he/she does a summersult. at the same time say summersult then click the clicker (if you don't have a clicker use a pen clicker or your tongue) Once you have clicked it give him/her a treat. do that over and over again until you can do it without the clicker, pen or tongue. if you want you can add actions so you don't have to say it.
2. pretty wings/flex
wait till you tiel has stretched his/her wings out. click the clicker, tongue or pen and say the word then give him/her a treat. do that over again till he/she has leanrt it you could do actions as well.
3. fly to arm to arm
get you tiel on one arm and put a treat on the other arm when you tile flies over there click the clicker, tongue or pen and say fly. do i again and again till he/she knows
4. sing
you can either sing yourself over and over or put on some music ( i recommend singing yourself)
then you can say what you want him/her to sing then sing it her/she will eventually learn it
5. Wolf whistle
if you don't know how to wolf whistle get someone else to do it or you can get this CD disc on how to train you cockatile it has the wolf whistle on it. eventually he/she will get the hang of it and will not stop.