Jayber Tan offers some ideas on growing your Twitter audience on IndieHackers. Following key influencers in your niche, adding them to a list, and consistently commenting on their Tweets is a great strategy.
Twitter is my primary channel now to grow IdeaEconomy. I’m adding 4 or 5 newsletter subscribers a day now and it’s been less than a month since I started. I’m very happy with the results so far, but I can do more to keep building momentum.