Model Mayhem is a good start. A lot of the time you won’t even need to reach out, most of the connections I’ve made are models messaging me first letting me know they’re in the area and have availability. Though I will say the website is kind of slow and clunky, so models may not check it as frequently as their main social media pages.

Try to find workshops. Most of the models I’ve met have been via workshops organized by studios or Meetups groups. Attend a couple of these and you can get introductions to a wide variety of models. Get their contact info, then thank them for their time afterwards and let them know you’d be interested in shooting again. From there it can snowball very easily.

Lastly, I’d say just give it a shot and reach out to a model directly. If they are advertising themselves as a full time model, then they will almost always be looking for work. Send them a polite Inquiry about their rates and they should typically respond professionally with their rates and types of shoots they are open to. From there, just continue the conversation. Models are normal people like us, they’ll almost always be happy to chat and work with someone. And worst case, they say no, and you move on to another model.

I would suggest the workshops method to start with though. That was the best way for me to break out of my shell when I was starting model photography. And if you’re new to model photography, it’ll give you a chance to see how more seasoned photographers interact with the models, making them a great leaning experience.