Oh, I didn't do much to be honest, I created my linked in profile a while ago and fill description, photo, etc.
And then some offers start to appear. For me is kind of a mistery too because on the past years I received offers one every two months or so but after this clients offer I didn't receive anymore so I don't know is the market is saturated or what
My only advice would be to create a linked in and start posting all your projects there and see if people reach out to you.
Linked in is not the only platform tho, I have a friend that post his models on Instagram and he received offers there
Hope this helps! If you have any doubt let me know