It might seem obvious but being able to name your feelings is the first step to controlling them.
Kids who have a hard time with Emotional Control could cry for half an hour or more without being able to stop or stay upset for a very long time no matter how many times you ask them to move on.
There are a few ways to help them manage their emotions. If you want to start early like I did with my toddler, start with simple games where they learn to:
Name the feeling and Recognize it when they see it. (which will also help them to read social cues)
For toddlers, I recommend Role Playing games https://www.mrmizrahi.com/collections/role-playing-toys
For teens, you can play Chance Games; they will teach your kids that they cannot control everything and to be more flexible when something that they don’t like happens. (https://www.mrmizrahi.com/collections/learning-flexibility)