I believe that good contact with community is the best way to do so. Dash is an excellent example of this. Listening to voice of actual crypto owners not only will assure that they will stay with it but also will attract new people - sometimes new solutions implemented that way are very interesting. For example, FuturoCoin is now adding new masternode system - it will generate passive income for masternode owners, which will definitely be attractive also for new users.
I liked to think that communities help developing some projects, but sometimes they don't, and i think it's very improtnat to support each other in cryptoworld. Speaking of FuturoCoin team, they are doing pretty decent job with promoting their altcoin, not only making this masternode changes, for example they recently signed a huge sponsor ship deal with one of the Formule 1 teams:
https://www.businesswire.com/news/home/20190205005454/en/FuturoCoin-Unveiled-Partner-Aston-Martin-Red-BullI've senn many examples of altcoins sponsoring some sports teams or sports in general like Litecoin for example