I start by asking nicely, then after asking nicely a few times, I start using my stern voice, then if that doesn't work, I threaten that they won't get their reward stars. However, if that doesn't work, then I'll usually lose patience and start yelling. I don't want to yell at my DC, but don't really know what the next step is if they're still not doing what I asked them to do. What do you do if you've asked your DC to do something many times and they just ignore you?