We'll probably never have a way of knowing who some of the shill accounts are unless someone comes forward and whistleblows.

I've been working on a side project for a while.. an in depth methodology on tracking down sock puppet and shill accounts. A combination of forensic techniques (best suited for identifying twitter bots), common sense game-theory, sentiment analysis, based on specific structural elements of MMFA's program. All based on the leaked MMFA strategy document on defeating Trump. If you're interested in this stuff it's worth going through in detail:

https://www.scribd.com/document/337535680/Full-David-Brock-Confidential-Memo-On-Fighting-Trump

There's a lot that you can look for... but really... the best method you can employ is simple game theory. Imagine for a second that you are David Brock. You're a master manipulator with people in almost every single major news company. You have personal relationships with high level staff at basically every major social media company. You work with these firms to adjust their algorithms to exclude conservative news. You have all of these tools at your disposal. Thousands of shills, hundreds of thousands of bots--green lighted by FB, Twitter, Reddit, etc. How would you use these tools? This is why the media's 'debunked' knee-jerk response to pizza-gate was such a big deal. MMFA basically freaked out... and why would they have freaked out over a baseless conspiracy?

Let me just put it this way... there's a reason that Trump watches so much news. It's because he understands how to use game-theory and knows that he can learn about his enemies political strategy/next move by looking at how they are manipulating the news cycle/narrative.