Using DF you are going to get people that have never done these fights before. So they need time to learn. You can watch all the videos you want to watch. It's putting those tricks into effect that is the tricky part. Give people time. Don't give up so easy. If you notice somebody doing something wrong, coach them on what to do that could make them better. You're not going to get the best group ever using the DF, so you need to make due with what you have. Don't forget, everybody has a different play style. Just because that is not how you would play the job, doesn't mean that they are playing the job wrong.