There are a lot more women now sailing at my home spot here in Finland. I think there was some sort of culture change a few years ago: there were more demos & basic windsurfing courses at the beach and we got a whole lot of new people into the sport. In addition to the demos & courses, the local club also started improving the shared gear that the club provides for members.
From what I have seen, women seem to prefer to plan well ahead, so they don't mind that they have to reserve the gear on a web calendar. The calendar also allows them to be more social: they can book the same time slot as their friends and do the rigging and sailing together. Most of the women who started a few years ago are now on their first or second board of their own. A few of them are still using the club gear.
So, my advice would be to improve the social aspects of the sport. A simple web calendar goes a long way in achieving that.