Good cover and blurb are a MUST DO! Without them, any promotion or social media won't work well. Since you are asking for a growing base without social media, I can't say it was a bad move, but...At least an interaction in a forum is a MUST DO as well.
Join the forum, search for the related topic which related to you. Don't simply drop your link without a proper introduction. Don't follow the trend of subs for subs. Discuss, advise, and comment. In that way, the more you interact, the more without your conscious you'd grow your own circle of friends and admirers.
Among all the publishing apps that I've been using since 2016, this was the only one that was friendly, helpful, and kind to motivate us to move forward.
I like it here, Tapas was the only place that has REAL people read your work.
At least, that was what I believe now.