I usually collaborate with people who have booked/worked with previously. I also offer collaborative sessions on projects I have never done before or projects I really have an interest in. After a session, there is also post-production. It's important to note the effort and overtime that goes into providing the level of quality that is produced, even as a collaboration. With some variables considered, I've developed three standard collaborative options. Home Collaborations, Local Collaborations and On Location Collaborations.