Use online tools like Google Street View, neighborhood data sites, and even local Facebook groups to get a feel for the area.

There are some great tools out there always, but get connected and network as much as possible.

BiggerPockets is working on tools for exactly this! 

You can get the Bigger Pockets paid membership and use their Find a Market Tool to analyze.

A Proven, Repeatable Investment Model - Even a small number of deals, executed consistently, can be more valuable than sheer deal volume.2.

Another tool that is really excellent for this is Pricelabs.

Knowing what NOT to do is often the most valuable advice!

Don't be afraid to go low Sunday through Thursday to get some activlty.We use Pricelabs, but only as a tool; I have to override it continuously.

What I find to be most valuable: Ease of use, cost-savings and efficiency and here's what I mean: If using an interior designer to furnish your rental, they will hand you a list of supplies + furniture to buy and what I was able to do with Minoan is upload that list as a CSV file and then they come back with a quote of all of the items they can fulfill along with their respective discount. 

Having before & after pictures is a string tool when dealing with HMLs and real estate agents to gain business.