Virgin Islanders and especially St. Johnians are friendly and most times very gracious people. One custom that is very important, however, is to "remember your manners" when approaching or conversing with locals (even those from "the Mainland"). A salutation of "Good (Morning, Afternoon, Evening), How are You?" is not only proper but expected before starting a conversation.
Also, bathing suits are only appropriate while enjoying St. John's beaches; when off the beach a cover-up or other clothing is island custom.