[header] How to coach a kids' soccer warm up drill [title] Get them to perform a pulse raising activity. [step] This gets the blood pumping and prepares the players both physically and mentally for the session. There are many ways you can achieve this : [substeps] Get them to run some laps. 
This doesn't require much supervision or guidance, so you can set up drills for the rest of the session at the same time. And you don't even need cones! Another fun way to get them warmed up is games like' stuck in the mud'.