I think the best form of marketing is word of mouth, if there is a good project then they don't need to shout it from the rooftops, people will realize the potential and they'll tell others about it, soon it will spiral and the project will be very popular.
Word of mouth marketing methods are good, but of course people who provide information must have good trust, because people tend to follow other people who are above or smarter. If people who give information do not have trust, then it is useless