Keep fingernails and toenails short to prevent hurting yourself or training partners
Remove jewellery or cover it up before the lesson to prevent hurting yourself or training partners
Tie long hair back
As you enter/leave, bow with both feet together and say "oss"
Try your best
Refrain from foul language and violence
Refer to your teacher as Sensei, never by their name alone
Using sensei as a title before or after the first/last name is also acceptable e.g. Sensei Simon or Apen-Sadler Sensei
If late, warmup if possible without interfering with the class and kneel at the edge of the dojo where the instructor can see you. You will be invited to join the class when it it safe to do so
Never just join in a class without permission - this could be dangerous, and is also disrespectful
Help your senior grades / instructor(s)
Example - If you see a senior grade sweeping the floor before the lesson, offer to help