It’s a good idea to start with MAM since they have interviews twice a week, and you can access invites for other trackers in the forums once you get to vip (which requires 4 weeks of membership, and a ratio above 2.0)
One of the nicer things about it is that you can gain bonus points (which is how you buy extra upload credit and VIP) just by being an available seed. Due to the shear number of books on the site, you won’t be seeding often, but they make it desirable to keep it available in case someone needs it by giving you a certain number of bonus points per hour depending on various factors.