Join a FB group for photography meetups. There are a lot of other people looking to build out portfolios, including models.

Network - events, meetups, groups, practice, other photographers, etc.

Figure out what your niche and target is. Then you could build a business geared towards that.

If you’re in the visual space, which photography is, you also need a website because people will expect to look at your portfolio.

Build out social presence. I’d recommend starting small and focusing on a single channel and Instagram would make the most sense.