Classroom management advice

I went back and visited my main placement on Friday and walked into a big surprise! The well behaved class I had left in September had definitely undergone some transformations. My master teacher warned me that this would happen as they got more comfortable, but I didn’t realize how serious she was! They were still the very sweet students that I left of course, but obtaining their attention was extremely difficult and keeping it…. Not possible! I know part of it was simply their excitement in seeing me since it’s been over a month. However, I feel like I need to go back in January with a game plan! I really don’t want to use punishment in my classroom management but the only idea that I can imagine working is card pulling. So, I was hoping that someone might be able to give me some feedback for some positive discipline I could use to ensure that I have control of the class but also to ensure that my students keep their integrity. I really dislike going into classrooms and seeing the same kids cards pulled all of the time. What can I do to keep those kids motivated to behave?