Newbie - Analysis Tools - No/Low Cost

[Monica Gonzalez]

I'm looking to start with Multi-Family (duplex/triplex).  I have my own home so this will have be as an investor with 20% down. 

I know there are things I need to do to analyze if the deal is a good one, like rental rates, Status of the house/infrastructure, amenities in the area but what else should I be thinking of? Tools that I see to analyze deals: Zillow, rent websites, craigslist what other tools do you recommend?