Hashtags work. They get your posts in front of more people, and what could be better than that? Hashtags are on Instagram, Facebook and Twitter, they are searchable and clickable on each network too. A recent post on Kivi's NonProfit Communications Blog gives you "Everything you Need to Know About Hashtags."
Here are some hashtags from this post on "Hashtags for Every Day of the Week (Nonprofit Edition)"
What are your favorite hashtags?