You never know unless you try / 404 no silver bullet found
Will my employees work hard? Will project A give me more than project B? Is this partner good for me and my business? I think I'll hire a marketing consultant, executive analyst and spend some money on fat books, it sure will help!
Business is like loosing weight, there is no silver bullet, you just go and loose your weight...or you don't.
Want to check out a man? Do a project with him, and with simple knowledge that people actually never change, in a week, you'll know everything about him - his skills, estimations skills, and so on. Not sure about your project? Do an ugly buggy prototype, if someone says "I'd use it if it wouldn't lag so often" - go on.
If you think that doing nothing you loose nothing - you actually lost twice.
Experience is priceless, failures are bless, stagnation is death.