I agree with post 3 about what Marzano's principles stress, but these are also the hallmarks of a teacher's own methods of keeping the class moving with no delays to allow disruptions to occur. With middle school students, a teacher usually has to demonstrate in the first two weeks of school the procedures to be followed for where to find assignments when absent, how to turn in late papers, where to get yesterday's notes or handouts, how students are set up in groups and how you wish them to change groups, and what should be on their desks. For example, if the teacher has the schedule for the week written on the board or accessible by computer, students know what is expected and you eliminate the line of questions at your desk. The main concept of the day also helps to have listed as students then know what specific knowledge the teacher expects them to gain that day. Then they can answer the teacher's wrap-up questions to see if they understand that day's concept which sets up a positive start to the next day.
iObservation is based hugely on Marzano's principles of classroom management, and in his observation checklist, he stresses being able to see what the teacher actively does to establish classroom rules and procedures. Time management would definitely go hand in hand with that, because you should have proven procedures in place that can help with time management, such as how students move from small groups back to their individual desks, how papers are passed out, exactly what they should have out and be doing when the bell rings. These little behaviors really add up in terms of time management, and if you can streamline the process, that will go a long way in saving time overall.
If you are looking for ideas for how to make the observation process more time effficient, I'd suggest following the practice where the observed teacher offers three or four areas in a short list given to the observing teacher/administrator.
These areas can be areas of strength or weakness and these will guide the observers feedback. Focusing the critique on these areas can serve to give the teacher being observed some extra comfort going into the observation with a good idea as to what will form the core of the critique.
Also, the observing teacher does not have to prepare much before the observation nor construct a rubric or checklist.