I have nearly 2000 people on one of my online business accounts. I share not to brag because 2000 is small change in comparison to many others. Also shared to say that that number grew and is growing organically over the past two years as I believe due to being organic myself. Posting everyday, or every other day (be consistent). Start conversations. Post nice but simple things with pics asking, "How's your day going?" It's all about letting people know that there is actually someone on the other end. Someone who can and will relate to them. Response is so key. Stay connected. Offer your services. Tell them about your services. Let the others know that you are real. You care in some form. Just keep it real and be consistent. Organic can be slow, but it's real. 

Best Creative Regards.