Play in game chat and go with a party of 4. Look for people who are actively playing the objective or "communication". Once you grab two invite them to a party. Play few games then (throw the bait), tell them about CAG in the "simplest" way possible. This method has worked for me in the past and I'm almost certain works 90% of the time. Now to do this method it can cause issues since you could lose games or what not if the other two don't listen