Repeat after me: Twitter is the Shitter.
Trying to grow a brand there is currently a very bad idea unless you have massive $$$ to spend on ads. And F4F is only going to give you fake numbers with zero acutal engagement.
Look hard at the people who are effective there. They are either big spenders, or they brought over an audience that they had already built up elsewhere.
**No one in their right mind is focusing on organic growth on Twitter.**
Twitter is the Shitter.