I've been x-posting to other tribes with similar interests. Mine started out slow as well. Getting /t/Tutor off the ground was a struggle but if you keep posting great content the will come. /t/Tutor had 3 members for a week and then I woke up one morning to 20 new subscribers. If I find interesting content on that while I'm hunting for other Nintendo goodies I'll be sure to toss stuff up and include Tribes that will have an interest.