As for if an area is on the rise or on the decline you have basic demographic trends.  

You are correct property values in Phoenix have drastically appreciated over the last year, Tucson seems to be following a similar trend.

Looking at housing trends over decades you would expect a down cycle every +/- 7yrs.

The trend is your friend.  

Is Zillow (or Trulia, realtor.com, etc) a good place to get comps or do you really want to use Trend or have a real estate agent run them for you?

hi, so I'm looking to invest in the new london/ groton ct area in a year and a half. so I started my due diligence by contacting a few realitors in the area and told them what I'm looking for. this way I can start some trend analysis. but all I'm dealing getting are these lists of multifam's that went on the market this week with little to no info.

Stick to one spot and become an expert in market trends, demographics, and neighborhoods.

This trend is not over.

I currently subscribe to the MLS in my state and I see a lot of flaws with the system as far as finding deals in the market place and keeping up with trends.

Regarding down payments, I think the government put in place the 3.5% FHA down payment because there was/is a general trend of buyers not having sufficient down.