Yell At Them
Make sure you yell at your kids to play/work harder. Like, really loud. Also, be sure to yell at them when they make a bad play or aren’t doing something properly. They probably don’t realize they’ve made a mistake, so it’s up to you to point it out. Loudly.
Note: Sometimes your kids are working so hard they can’t hear you, so it’s important you yell louder.