The term "classroom management" doesn't have just one definition. However, it most generally refers to the way in which a teacher or instructor sets up the classroom so that students can learn most effectively. Setting up the classroom can mean both physically and how the teacher structures the day. If you're thinking about how to manage your classroom better, be aware of the some of the things that may affect the way you can manage it.
The environment can have both noticeable and unnoticeable effects on how well you can manage the classroom and how well the students listen. For example, if you have a full classroom of 30 students, then the students in the back will not hear you as well. The environment doesn't allow them to sit closer. This also accounts for windows and other students that can cause distractions. While you can't predict every distraction, you can set up the classroom to encourage students to look where they need to. For example, pull the blinds and shut off some lights without completely darkening the room. Make it brightest at the white board or on you. Students will then focus on that area.
How you set up rules in your classroom will determine if students keep those rules or not. For example, instead of telling the students what the rules are, develop an activity that lets them create the rules. It's a lot easier for you to call a student on a rule if the student helped create it, as opposed to if you just told the student to follow it. This goes the same for assignments. While you can't let students decide the guidelines, you can talk to them about what your guidelines mean. This will help them feel like they had a say in creating the assignment.
Students with disabilities, leaning or otherwise, will always affect the way you manage the classroom. If one student has a learning disability, you may need to spend more one-on-one time with this student or allow a development technician to work with him. This can distract other students or leave them feeling alone. Either way, they may act out. There is no one way you can handle these situations. However, you can decrease distractions by enlisting a couple students to help the student with the disability. If this doesn't work, consider setting up a quiet place for the student with a disability if he has a technician. Let the student use the space when he needs extra help, and stay with the class otherwise. This removes distractions, but let the student with a disability still be part of the group.
Social construction research teaches us that nobody walks into a situation as a clean slate. When students come into a classroom, they bring all the social stuff that happened that morning or the night before with them. This might mean that a family member is in town, causing them to get excited easily and not focus. Or it might mean that their parents are fighting and the student doesn't feel well and ignores you. The way you manage the classroom may trigger something from the home life, potentially causing the child to shut down or open up. While there's no way to predict how home life will affect classroom management, being away that it does affect it can help you adapt better and help student get through whatever they are feeling.