Before contributing to a mailing list for the first time, ask for help from someone who knows how. Sending mail to a mailing list is simpler than learning to drive a car, but it's at least as difficult as talking on the phone. Mailing lists are all different. Before posting anything to a list, read its introductory message and read some postings by others in the list as well to get an idea of its general focus. Remember the person.
Electronic mail is written and read by people.
Write messages people will want to read. Label the message. Messages without subjects are time-consuming to interpret, difficult to follow, and difficult to file. Write for your audience. Use language, references, and subjects that the readers of the list will understand.