There are some pretty solid standards of conduct by which you can almost never go wrong:
- Be on time, or a little bit early.
- Don't take long breaks.
- Don't leave early, and even stay a little late sometimes.
- Under-promise and over-deliver.
- Don't badmouth others and try not to speak of others unless they are present.
- Keep your word.
- Keep confidences.
- Be an accurate source of information.
- Don't keep other people waiting.
- Overdressing is better than under-dressing.
- Practice old-fashioned good manners, saying "please," "thank you," "you're welcome," "excuse me," "I'm sorry," address people as "mr.," "ms.," "sir," and "ma'am."

If you follow these old-fashioned rules of conduct you can almost never go wrong.