You have to become a LEADER! You have to know where you going with this business!
Then just share what you are doing with your team on a CONSISTENT basis. Your team would see that you are serious about business and they will follow you.
Good idea to send weekly messages, but also you can create and promote your own contests (doesnt have to be expensive) and send a personalized messages to people who are active. Always encourage them to ask questions and provide feedback to you.