The following is a short-list of the expected repeater etiquette. Please see the FULL expanded list here. for more detail.

1. Listen for traffic before transmitting - Don't just break in unless there is an emergency.
2. Always identify yourself according to the regulations - every ten (10) minutes and at the end of your transmission.
3. When identifying or checking in to a net just use your call letters
   • DO NOT spell out your call phonetically unless asked. 
   • We don't need your name, where you are from etc., especially when checking in to a net. We can look that up if needed. This is rude as it ties up the repeater and delays others waiting to check in behind you.
4. NEVER ker chunk the repeater to view the signal strength of the squelch tail. This is a nuisance, and it is illegal according to FCC Part 97 rules.
5. Do not use Jargon, 10-codes or Q-signals
6. Avoid lengthy conversations, and pause between transmissions to give others a chance to break in for emergency traffic.  Long conversations should move to simplex if possible.
7. Do not just jump in to other peoples conversations.  This is incredibly rude if you were not invited.