Most creative people are motivated by the potential of what they want to achieve and the competences they wish to acquire. They are looking for transformational business opportunities, rather than transactional relationships. Why treat project teams as if they were disinterested contractors when you can treat them as they are: entrepreneurial stakeholders?

Providing that you pay them enough, i.e. the market rate, they will be motivated by the potential of achievement, yours and theirs.
Don’t delegate in a remote uninvolved fashion when you can benefit from real engagement and frequent communication.
Don’t adopt a superior to subordinate posture, when you can develop a generous, committed and rewarding partnering arrangement.
Respect the creative process, develop trust not defensiveness, coach each other, and empower them to empower you.
Share your vision and purpose, explain ‘why’ when you explain something, encourage leadership at every level, stoke the energy and smooth the stress.