Here’s my one caveat, if you’re bothered by a lot and expect quiet student perfection, this might not be the classroom management plan for you. But if you want to share a mutually-owned space with students who crave independence, yet want help through tough tasks, this might help you start your school year off with your patience intact. 

Here is what has worked for me for twelve years of teaching high school ELA. The difference between teaching freshman English through senior English is the amount of repetitive training these procedures take and the power of your consistency up front. 

1. I don't assign a seating chart for the first week of school. This allows me to see cliques, good situations, and distractions. After the first week of school, I only move students who have shown they can’t handle sitting by their chosen seat partners. This shows I see the students learning while sitting by friends, and it shows the distracted students that I see them more successfully someplace else. (Of course, if students have an IEP or 504 Plan, I follow those seating preferences regardless.) 
2. I establish a routine of picking up handouts or materials from a table near the door, so I don’t waste time handing one paper to each student when needed. By the end of the first month, students automatically grab what’s on the front table. 
3. I establish a consistent place for extra materials, such as lined paper and pencils they can access without permission. If students need to get a pencil or sharpen one, blow their nose, get a sheet of paper, they can function independently without disturbing me. I reinforce that this classroom is their space too and there’s no need to ask permission to get something they need.
4. Our school has a policy that I love that eliminates bathroom pass insanity. For the first 10 minutes of class and the last 10 minutes of class out of our 45-minute class period, no one leaves the classroom for any reason (other than an emergency). This eliminates bathroom interruptions. Also, only one student is out of the room at a time. 
5. My cell phone policy uses a traffic light symbol. On slides for the lesson, I put a circle on the corner of each that is either red, yellow, or green. The colors correspond with their allowance of using their cell phones. If they do not follow the rule, they get one warning and then I take the phone to my desk for the rest of the period. If this is a repeated offense, I contact home after day two. 

This isn’t foolproof. There are some class periods where I have to remind them longer or a few students forget to pick up materials, but for the most part, it’s eliminated my frustration over common sense lapse in teenage classroom behaviors and kept my patience. Take what works for you, try some out, or modify as appropriate. Good luck!