Social media (specifically Instagram) is ruled by the hashtag. You may have the best pictures and content and still not get noticed without the right tags. This last month I spent some time researching the top portrait photographers in the US and on Instagram to find the best hashtags. Here is a short list of these creators: Joe McNally, Eric Lafforgue, Peter Hurley, Rehahn, Dmitry Ageez, and Martic Schoeller.
While the following list is filled with some of the best hashtags for portrait photographers, do not use these without some thought. Make sure that the tags you use are applicable to your content.