THe best thing that I have found with any dive buddy is communication. It takes a while for one person to "fully" understand another persons signals underwater. When you get out from the fisst dive, explain what you meant by a signal if the other person did not understand. Also ask (in a non-judgemental way) what the other was trying to say under there. Some thing like "What did you mean when we were by the wreck and you mad this gesture, I was totaly lost for a meaning, I hope that we did not miss anything cool." It has worked for me in the past, you eventually get a feel for one another. PADI has lots of signs but not enought for complete communication, especially with a newer diver. You would be suprised how you can turn a bad into a good if you both have a better understanding of one another. That being said, there are people that just do not get along...