The easiest customer to 'do more with' is the existing customer you have. You have two projects (presumably two companies), reach out to them and ask them where

The easiest customer to 'do more with' is the existing customer you have. You have two projects (presumably two companies), reach out to them and ask them where else they need more help, "what other projects could we help with?" If you're doing a good job then it's natural. It's all about forming a strong relationship at different levels in your customer and having them advocate to use you in other projects. The other tactic is that your customers know other companies and contacts in the space. Ask them for help - "as a new consultancy we're trying to build our contacts in healthcare, is there anyone in the industry you think we should speak to?".