With children it can be very helpful to use actions while the music is playing - that saves everyone sitting around like lemons!
Bear in mind that actions can be done to ANY song - not just Head Shoulders Knees and Toes.
For example use this great game as part of your pre-teaching:
Show a flashcard and name the word and make a symbol for that word.
Every time the class hear that word they make the relevant symbol.
Once you have pre-taught any keywords in the song using the above game and other listening games play the song, have the class listen out for the keywords and make the relevant symbol.
Make up any kind of actions or movements that feel nice to perform to go along with any instrumental parts. The more movement you have the more the class are actively engaged in listening and participating in the song. That gives a more memorable result than sitting at desks and listening, or even trying to fill in a gap fill while the song plays.
There are some useful song sites in this post and here is one more:http://www.teachingenglishgames.com/eslsongs.htm