I get the flat roof warning, but most commercial buildings have flat roofs, so there must be ways to do them right.  

Our area has unique retail flip opportunities and I am wondering if there are any thoughts, warnings or other tips out there for me.

If you one a 200k property free and clear and it's bringing in $1200 a month in passive income, you should be able to take out a mortgage for 150k, and use that 150k to warn you $1500 a month in passive income on additional properties. 

My biggest warning is the permit inspection process.

There should be a warning somewhere mentioning this to beginner investors to do double diligence.

I will say that California is cracking down on mobile homes and most cities are fighting against them, just fair warning.  

Just a fair warning.

BUT - buyer be warned, unless the Ander is provided in writing and somehow signed, it may not be the truth or at least not the whole truth.

Here is a fair warning to all newbie investors that are on a wholesaler's mailing list. 

I would warn that its very tough to secure listings for large multi family or SFH portfolios over $1M to list on MLS.