People can give you perspective, services, an eye on the property, whatever you need. 

I'll keep an eye on this thread - I end up down your way regularly.

HML's are used to these deals and can be a valuable second set of eyes to help you evaluate a potential flip, your associated finances, and keep you out of trouble.

From the county records of how much a property transferred to, to demographic and employment data, rental rates on zillow, trulia, rent-o-meter, street view, birds eye view, etc etc etc.  

Experienced eyes can see things which I may be missing.

It is important to keep an eye out because sometimes signs aren't posted on the curbside,  they might be inside the windows if the agent feels that there is likelihood the sign will be stolen or disappear.   

No one has said it here and you may have your eye on this already but pay attention to timelines and holding costs.

He keeps an eye on the recycling bins to make sure people are recycling properly and takes out any trash that ends up in those.

This is a huge eye opener for me.

When people give me Zillow zestimates I just roll my eyes.