Be prepared for some difficulties along the way. It takes several months to learn how to roll and fall smoothly. Be patient with yourself. This is not to please the instructor, but is part of the authentic traditional Aikido training process. It is the same in all Aikikai dojos throughout the world.
Good etiquette includes arriving in good time for all classes.
If you arrive late for class, wait for permission from the instructor before stepping onto the mats and joining in. If practice has already begun, warm up by doing some stretching exercises. Never try to force a technique. The object of Aikido training is not to get a person onto the ground by any means. Respect the interests and condition of other people.