Debrett's, which publishes a range of etiquette books, said: "We share so much information and network through many social media channels - often to the detriment of face-to-face skills."
The course will ask youngsters to examine their social media profiles and see what information is available to the public.
Tips include not pestering friends to join groups or forums and replying promptly to comments or tweets. It also advises that cards or phonecalls to friends on their birthdays mean more than an online post.
James Field, training manager at Debrett's, said: "When we put our lives online, we are creating an idea of the sort of person we might be for others out there."