Open mikes are a great way of getting on-stage experience and they are good places to try out new material, but they are seldom launching pads for careers. You must do much, much more to build up a following, including playing at small, non-paying festivals like NEFFA in Massachusetts. Also try campus pubs, cafes, libraries with music programs, high schools, community centers, charity fundraisers, and any place that will be willing to have you for little or no money. But you will get heard. You should also check out some of the community song circles that have been popping up all around North America (and probably elsewhere).