Keep that day job
First off, keeping our day jobs was a big one. If I and a few others had dived head first into this full time, we would have run out of ramen noodles to eat pretty quickly. By making this a part time side project, we were able to sustain an income to help offset the efforts on this.
In fact, I am still in both companies even today – I feel no immediate rush to focus on solely one, if I can hire the right people.