Hey Daniel! Great question. As you mentioned, the deals environment is very much fuelled by the relationships the various parties have established in the past. Therefore, networking actively becomes a key part of this business. This may involve attending conferences, networking events, product launch events, or any such events where you have an opportunity to meet professionals and business owners. However, networking can also happen anywhere else - like at the gym, or coffee shop. It's all about building a network of connections as you never know where the referrals may take you. Keep in mind though that you should be genuinely interested in meeting people first, and seek to build trust in the relationship, as this will lay the foundation for them to reach out to you when they have a deal that you could help or be involved with down the road.
Ofcourse, the other alternative is to market your skill-sets/previous successes which would attract parties looking to enter into deals, and would want your help.