Squash and Stretch.
Just before the dragon lands, I have made the tail lift upwards and then slam down on the ground when he touches the floor. This is to give some indication that the tail is heavy, and I didn't want it to look still and although it isn't part of the dragon's body. I also kept it moving from time to time whilst the dragon was standing still, to help show that he is either happy and content, or not so much.
Anticipation
Before the dragon blows fire, I made a point of making sure he inhales for a long time to give some indication of what is about to happen, and to make it a big deal. If the Dragon just blew the fire without bearing in deeply first, it wouldn't have the same effect.
Exaggeration
When the characters are happy, I made the eyes suddenly larger to show the sudden change in emotion (also i thought it would add to the character appeal because it makes them look cute!)
Secondary Action
I though having the dragon suddenly blow smoke out of his nose would reinforce how angry and offended this character is, also it makes it slightly more comical.