Rules of any classroom are not just about controlling the masses of teenage hormones and reigning in the attention of students but they are also about safety, and in art that is imperative due to all the hazards of an art classroom. In the art room there are heavy, sharp, hot, and spinning tools of chaos if students are not acting the way they should be.

First of all, behaviors have to be started the first day of classes! And they have to be consistent, not only consistent in the amount and ways you apply them but also that you apply the rules to everyone, always. PREVENTION is key! This does not mean you have to have a long lecture about behavior and scare students away from touching anything. It means that you control the situation that students start the semester off with. You introduce them to safety rules the first day and set a reasonable amount of rules for the classroom. The first day preface the semester by saying, "You can choose where you sit, but that is a privilege, and if you are not able to complete work on time due to talking too much or other distractions, or you distract another student, that privilege will be taken away and I will come up with a seating chart." Do not be afraid of implementing a seating chart the first day, it is important to decide whether or not your students can handle it very quickly because the habits that they develop the first week will continue through the semester. Another easy way to be preventative in nature is to know your students, know how long their attention can be held for and be able to get through the lecture quickly and have them working. Most instances of misbehavior or of incidents at all are most likely to occur during transitions so keeping the classroom flow and fast transitions are important.
Another point that is important to make is how to be preventative by being proactive and getting to know your students. Listen to what is going on in the hallways before and after classes, get to know their behavior and take an interest in them daily.
When prevention is no longer an option, you need to go about intervention in the least disruptive way possible. How do we do this? Well first start out with small warnings, they don't even have to be verbal. If a student is talking during your lecture go and stand closer to them, your presence will remind them that they should be listening, if this doesn't work try touching their desk. If the whole class is being too loud and you are trying to get their attention, try not talking. See how long it takes for the students to notice. If this doesn't work go to the door, turn off and on the lights until the class quiets down. Raising your voice is a last resort, and another reason you don't want to raise your voice is it's ineffective in the long term, shows the students you are not in control, and is disruptive to other classrooms. Be cool. Stay cool. You got this.
When there is a consistent behavioral issue in class you may need to take time to pull a student aside. This is only when you have tried every other option. Taking a student out of class or out of their work is disruptive to the classroom (if you are lecturing,) and embarrassing to the student (if done improperly.) Public humiliation is unacceptable, do not embarrass a student into behaving, it's ineffective and will cause harm to the student. When talking to a student about their individual behavior that has now become a serious issue and you need to take them aside, approach the student in a concerned way. Do not attack or condemn the student's behavior this will shut them down to the conversation. Ask them why they are acting a certain way. Show that you care.
(Side Note)
I had a camper once who was the sweetest boy you could ever meet, at six years old he would hold doors open for everyone consistently said "thank you" and "please." He was just an overall blessing to work with. But one day he got into a fist fight with another little boy. I was extremely concerned as this was not normal and was alarming that it would disrupt the group flow so while another one of the counselors worked with the group I sat down with him and we talked. It turns out he had been being bullied (not by the child who he hit) but by kids he knew outside of camp. I asked him why he thought that was the solution to being angry. He said "I don't know, when I get mad I don't know what else to do, I know I shouldn't do it but I don't know any other way." So I told him whenever he felt angry he needed to come to me and tell me so that he wouldn't get hurt, or hurt someone else and that we could all have fun, and if he came to me I would help him calm down. Later in the week he came to me and we would count to ten, we breathed deeply together and he took time to think more clearly. Which was amazing for a six year old.
Back to Business!
If nothing else works and there is a confrontation, these are the things you must remember in a confrontation:
YOU ARE THE ADULT.
What that means is that you have a more developed frontal lobe, and have better (hopefully) decision making skills than a teenager. That also means you need to stay calm and speak respectfully. If this confrontation needs to happen take it outside of the classroom by getting a teacher to not only witness the conflict but also watch your class. You need to be objective when having this confrontation. Remember again YOU ARE THE ADULT. Be mature and listen to the student. A lot of confrontation in the business place (I think this applies most places) comes from people not feeling like they are being heard. And lastly but most importantly NEVER, and I mean NEVER touch a child!