A good figure model is usually an experienced professional that will make the session easy for the artist. However, finding that model may not be easy. Not only does it take some legwork to find models, smart model will demand proof from the artist that he is doing legitimate work. There are some online sources available, but give yourself some time to go through resumes and portfolios to find a model to match your vision.
Post an ad on Internet sites like Craigslist and dedicated model sites like The Figure Models Guild. The ad must explain what you expect from the artist, especially if you want to do nude drawings, and what body type and age you want. Check the model ads on the same site. In Craigslist, search in the "Artists," "Creative," or "Talent" sections.
Attend a figure drawing co-op for a few weeks. A model may enjoy the chance to work one-on-one with an artist. It's perfectly acceptable to approach a model after they finish working and ask them whether it is ok to contact them about modeling for your project.
Speak with any art teachers in the area that hire models for classes. Most figure models do not work full-time at one studio or school. Those teachers may be willing to contact a model for an artist they trust. Be prepared to show the teacher your portfolio to establish your credibility.
Once you've heard back from a few models, ask them to submit a clothed picture so you can see if their look will work for you. Set up a time to meet with any potential models in a public place. Bring your portfolio, and be prepared to answer questions about your art and the place where you work. Ask the model to bring a portfolio, and proof she is over 18.
Use the meeting to establish pay and working conditions. Most models charge by the half-hour or hour, and most will require a rest period or two during a session. Standard practice dictates that the model work 20 minutes, then have a 10 minute rest - however this can be altered within reason if both you and the model agree. Artists usually pay their models after every modeling session.