I want to add that I think what should really count as "popular" is true audience interaction. A comic with 10K subs and 1K active interaction (likes, comments, sharing etc) vs a comic with 6K subs and 2K interaction. Well, the latter is doing better. Active audience amount is always always always going to be significantly less than the total subs (even on Deviantart this was true, without doing comics), but never let it phase you. Your biggest concern should just be interacting with people who care enough to leave comments and likes consistently. Numbers are largely useless and can cause some unhealthy dependency (constantly seeking validation) on strangers. Nothing pushes people further away than desperate cries for attention - and sadly I am watching a friend go through this right now.
Not saying you shouldn't advertise yourself, but just suggesting that a more productive approach should be 90% of your attention on the people already present.
