Finding those on social media who have influence has always been a challenge, but a crucial one to master.
How else are you going to focus your efforts on those who matter for your campaign, issue or company? The Tools I use to do this are:
Bluenod: http://bluenod.com/product
Visualize Twitter communities and find who is influential in them
Riteag: https://ritetag.com/
Finding the right hashtag to use to get your Tweets seen.
Followerwonk: https://moz.com/followerwonk/
Analysis of your Twitter followers, who are they, what are they talking about and when is the best time to post.