Have you posted casting calls here? You may get a few flakes who won't show up but some will and that will be a start.
Offer a nominal fee for a shoot, say $50, you invested in equipment you may also need to invest in models to start your portfolio off.
Network, network, network, ask friends, family, coworkers to pose, join a local meetup group or camera clubs who might shoot models.
Nothing succeeds like success, once you have a few decent images then you will find you will have more models contacting you for shoots, but you will have to work and possibly pay to reach that point.