Tips tricks ideas to think of before hiring a developer

I have a project in mind which I'm confident will make money. I already have the customers I just need the product. I built an app and I think my biggest problem was I stepped back and let the expert be the “expert”. We ended up closing the project as it was a dud. Sandboxing also took FOREVER so the project took over a year and a half before I was even comfortable enough to present it in a social setting.

Do you guys have tips for this time around (aside from the million takeaways I've already noted to myself) on how to make this project more efficient? financial tips are also helpful!!