So.... you can begin with requests. When the individual requests an object or drink... when you give it to him/her... follow it up with, "say, Thank you!" It helps if you say, "Say" in a quieter voice tone than the word you want the individual to say. Of course... when the child/adult imitates or says, "Thank You".. then praise, hug, or say, "your welcome"... make sure the child has your full attention as a reinforcer... in other words, don't turn your back after the child/adult says, "thank you". Make it a big deal!!!! :) If "Thank you" is a new word, then praise the child for attempting to say the word. If the child is unable to sound it out... then encourage the child/adult to sign, "thank you". Many people know the "sign" for "thank you" and truly appreciate it when others use this skill. It is a skill which can open doors for a child socially. Others like to be appreciated. So...... if you would like to be appreciated, then teach the response you would like to see. And.... do not forget to say, "Thank you" to your child/adolescent/adult when they do things for you! :)
Have a blessed Memorial Day!!! :)
Below is a site that demonstrates how to say, "thank you" in sign language.