Commercial (Retail) Analysis Components

[Troy Fisher]

So I know there are a lot of "Rules of Thumb" on the Residential side of Real Estate.  As I try to transition into Commercial (Retail) I find that I have no idea on how to perform the proper analysis.  

What are the Expenses that one needs to account for on Retail Commercial Spaces?

What are the "Rule(s) of thumb" that an investor should run quickly to evaluate a property?

What are some of the signs that the property could be a diamond in disguise?