I will speak for myself here. 1. The most important thing I look for in a business relationship is trust. But, for trust to exist, both sides need to be transp

I will speak for myself here. 1. The most important thing I look for in a business relationship is trust. But, for trust to exist, both sides need to be transparent and upfront throughout the development process. 2. One area that's always a little tricky is scope management. Make sure both sides agree what exactly is included in the scope of work, and what is not. 3. Working iteratively helps. Set specific milestones and sub-goals and move along towards the final product. This way, both sides will clearly know the progress, and can make tweaks and changes along the way depending on how things change. Software always evolves. 4. As for money - I would personally avoid a flat fee based project unless the scope is literally set-in stone (i.e. outcome is clearly quantifiable). Hourly billing rate coupled with these milestones should work well for both sides. 5. Post development support - this is again a tricky area. Be clear on what kind of post development support is needed - and its associated cost (e.g. dealing with bugs, minor feature tweaks). My two cents!