Ask HN: Starting a software business while employed full-time

Hello HN community, I've been nurturing an idea for a software product for a few months now, and I believe it has potential to grow into a sustainable business. The software product would fall under the geospatial industry. However, I'm currently employed full-time in Europe. I'm sure many of you have been in similar situations or have read / witnessed someone navigating this path. How did you promote your business / brand while being employed full-time? I've seen few opportunities to speak at industry conferences, but ignored them due to being employed full-time.