How do you know when you are getting better at chess?

I posed the title to this post to a group of junior players I coach this morning. As it is a school group, as opposed to a 'chess' group, answers like 'your rating goes up' weren't the most obvious ones. 'You win more' did come at the top of list, but 'you make less mistakes', and 'you stop losing pieces' were also there. But the answer I like the most actually came from my wife when I discussed the topic with her later.
'When you enjoy the game more'.