How could I start out bird dogging or scouting for properties for investors?

[Tyler W.]

I'd like to start building up my REI career by bird dogging properties for investors and making commissions or equity stake in the investments I find.

How should I start this process?

I have an idea of where to find properties- MLS, drive bys, craigslist, loopnet. But how do I know if a property pencils out?

What numbers do I need to know initially before marketing it to an investor? 

And where can I meet local investors to build a list of potential buyers? 

Does the chicken come first, or the egg? (Do I find investors first and then look for properties, or do I find properties and then look for investors for them?)