[joulseenjoync]

Call or write beforehand to ask for permission, unless their website says that visitors are always welcome. Arrive early. Leave your shoes outside the door. Introduce yourself to the sensei, if he is not busy with something else. Ask where you should watch from. Watch the whole practice, do not duck out early. Stay alert, especially if it is a small and/or crowded space - someone may come flying your way by accident. If you have questions, save them for after practice.