I'm a priestess of a kindred, and while that's not exactly like a coven (we practice different things) there are a few things I would suggest.
If youre looking for more members: Advertising the availability of your group. Perhaps put something in the paper, or start a free online blog/website where you give out information on it. This attracts people. If you're a part of a school you could always start a group.
Make sure to get to know each member well. It's always handy to know the interests and backgrounds of each member so that you can plan things every member will enjoy. Getting to know and understand the path or beliefs they each hold is important as well. Perhaps, since you're starting small, ask each member to provide some suggested topics you'd like to cover when you gather.
A calendar is something you may wish to plan. In my kindred we outline all the future gathering times, the celebrations and rituals we will be doing. This makes it easy to look ahead. Perhaps discuss some rituals/spell work you would like to see the group do eventually.
When it comes to what you actually will do in the coven, such as the content of what to discuss and how to run it, etc- I cannot help. I'm sure my Norse tradition is not the same as what you're doing. :P
Best of luck!