If you have existing subscribers who have special access to something new that others don't, consider using this as an invitational gift to others. Both Dribbble and Clubhouse have done this well, limiting the number of people you yourself can share invites with.
Where can you build in a referral system that seeds new subscribers based on peoples' own networks?
If we enjoy being reminded of past, positive experiences we've had, how can we spread these out in small drips over time?
Because we value certainty, we are motivated by curiosity. Where can you foster a desire to satisfy both needs?
We don't process and remember lists of information uniformly. How might you actually use this to your advantage?
Choice can feel overwhelming, especially for the uninformed. How can you instead default people to what is popular?
Those who are unfamiliar with what you offer need a little extra help to decide. Where might you provide defaults that guide?