Using visual aids makes communication much easier. It's easier for kids who are reserved or even those who are nonverbal to express their feelings.
 
You can ask questions about their feelings and allow them to use as many emotion cards as needed, as they might feel more than one emotion and even mixed emotions! 
 
There are also e-motions list" cards to help enrich their vocabulary, so if they use the word "sad" you could look at similar emotions and help them enhance their vocabulary.