Don't expect things to be better after break. Don't expect them to be worse. Go in expecting a lot of the same and work for something better. Your students, though they may not show it, will be relieved to see you after a week and a half away. You have also had a chance to breath away from one another for over a week. Now is not the time to revamp your entire classroom and management plan, but it may be the time to put your foot back down on the ground (or get it there for the first time) and keep it there a bit better than it was before the holidays.
The day after a break provides a unique opportunity to re-establish rules and procedures. Treat it like a fresh start in the classroom, going back over the rules like it was the first day. Concentrate on any of them that were working and if you think adding one or two will make a significant difference, make sure you keep them simple and that you can handle following through on each rule or regulation you want to cover. In the time that you've been in the classroom, it has probably become very apparent that not following through on a single thing you say is very damaging to your ability to govern your classroom. That's why it's important to keep it simple and concise.
A problem I had when people told me this last year was that I would go in to "lay down the law" and expect some kind of drastic improvement. That was always a let down. I would get frustrated after a couple days when one of my classes would go poorly and any small gain I made would go down the drain as I lost it in front of the class. Keep in mind that this is something that could help in the long term; it's not a fix-all, end-all. Regard the day after break as a starting point, not a day to fix all of the problems.
Go back over the rules you want to keep. Don't bring up any that you're going to let go. If you didn't have a sign with the rules up in the classroom, it might be the time to get one. The advantage you can use after coming back from break is just that: an advantage. Don't expect a fresh coat of paint on your management plan to fix all of the problems. Make sure the plan has your solid, core rules and make sure you stick to them better than you did before break. While all your problems won't go away, if you lay out the rules again and stick to them invariably, the students may give you a little back.
Today's Wine: Evodia Garnacha 2008. It took a little time to figure out what the grape on this was. It's from Spain, not too expensive and easy to drink.