When you particularly enjoy a specific Member's music and are regularly reposting their work, you can add them to your Starred List by heading to their profile and selecting 'Star Member':

If you so choose, you can remove them from your Starred List whenever you like by clicking 'Unstar Member' on their profile. You can easily identify your starred members on the campaign lists and your incoming requests (your Starred Members campaigns will also appear here), as the heart symbol beneath their name will be orange. You can also star / unstar a Member by clicking the heart:

Please note that for Artist Plan and Free Forever Plan there are limits of 50 and 20 favourite Members respectively. There is no limit for subscribers to Network Plan and above.