You need to decide on the "structure" of your site. There are various forms of membership site . The best structure for a paid membership site is to have a free membership and a paid membership ,having free content or even just a free "report" has proven to be a powerful way in bringing new paying customers to a site. By having free content available you are aiming for 100% of visitors to sign up for something.
A great option is to make a video course and have various modules for different facets of the niche .
This part is called fake it til you make it, and depending on the niche, you will need a certain amount of followers/fans. If it’s something like video games you should start with 10k or so. If it’s a small niche like underwater basket weaving, you’re probably good with having just 600 followers .You can accumulate these in various ways for free or paid .
Interlinking is a crucial part too ,as with any site ,not just so users can easily flick through your site but for search engine ranking factors too . I wont go in to any detail here as this is something that just cant be covered in a few lines and should already be a consideration before even thinking about a large content filled site but depending on the platform you are using can be made very easy to do with somethig like a related posts widget or even a simple blog roll.
I hope this helps you a little .