This is an interesting question from my perspective since I have been a student in lots of classes and I have been a teacher for lots of classes. As a student I want a class to be organized and have an intended goal that is achieved. I like the teacher to bring lots of examples to show the technique and resulting outcome. I also like to see hand-out material that the student can either use in class or later to reinforce what she has learned. Some classes are meant to be lecture and demonstration while other are hands on. The teacher, in the hands on classes, needs to demonstrate so all students can see her demonstrate. Then, the students need to go to their work stations (set up before the class begins). The teacher should circulate to all students with nearly equal time and offer comment to each one. For those who are ill prepared or not up to speed she should suggest additional help outside the class time. Achieve the class goal.
From the teacher perspective I need to be sure that the class has an outline projection and that it is followed so the students know what they are going to achieve in the class. They need to know exactly what to bring to class and whether or not they are required to purchase anything in addition to class fees. I most enjoyed teaching classes that materials were given to students when they registered for the class and had instructions for preliminary preparation beforehand. This meant that class time would not be wasted pressing fabric, cutting, etc. Make and display prominently samples for all to see. Encourage them to bring cameras to take pictures of our examples. Make your demonstration coincide with hand out material. Do not allow those who are unprepared in any way to derail the outline. Quietly encourage them to see you later-you may not be able to get them on track. If the class content is clear at the time of registration they should be able to discern their ability to participate. All have paid their money for the class and all deserve to go away with a positive outcome.
Whether you are the student or the teacher it takes quite a bit of preparation to have a positive outcome. I almost always ask students to fill out an opinion sheet-with no names required.