Don't you love simple, yet very insightful interventions when working with kids?  The feelings graph is a go-to tool for me.  I frequently use feelings charts during session, and they are certainly useful.  However, the Feelings Graph goes much deeper.  Instead of asking kids "What are you feeling today?"  I'd rather ask "How much are you feeling of these emotions today?"
 
This simple intervention is helpful in a lot of ways:
 
It allows children to show how much of each feeling they are experiencing.
It helps children take time to really pay attention to what is really going on inside.
It is a great assessment tool.  It can help you as a clinician to identify what feelings are taking precedence and identify what to focus on first.
It can show progress.  If I have a client fill out a feelings chart during one of our first sessions, I can pull it out again a couple of months later to help the client identify how their feelings have changed over time.  It can be a motivator.
It allows even very young children to express their emotions without relying on verbal language skills.
It helps children make sense of why they feel the way they do.
It can help initiate important dialogue about what has been going on.  The client may be willing to color in the boxes, but is hesitant to initiate conversation about something that is troubling them.