My tactic is this, and I've used this in several different circles – look for people who are moderately influential in a field, but not super famous (say less t

My tactic is this, and I've used this in several different circles – look for people who are moderately influential in a field, but not super famous (say less than 2k followers). Then follow them, and tweet positive things at them, or ask genuine questions, and contribute. There's usually a group of people who all talk to each other, and you can gently get into the conversations if you're careful. Once you do that, and you've made decent contributions a couple of times, they'll typically follow you. Now I can "ask Twitter" a question and get interesting responses from dozens of people. But it takes time and effort, which I suppose most people aren't willing to spend.