Curious if there are key search terms or tools that succesful listing agents use on the web. What do you think people are looking for online when trying to find and agent to list their home?
I know there must be a method that I am missing.

If you go to Google Adwords they have a key word "rater" that tells you how many people searched for particular terms. you can probably find something through trial and error

Yeah, you'll want to use keywords that have a presence but aren't ranking too high otherwise you'll get lost in the competition.

We've had some success targeting "what's my home worth" keywords, specific to the local area, i.e. Arizona or Seattle.

Whatever KWs you come up with, make sure to run them through these 2 free tools:
1. Google: will tell you how often the KW is searched
https://adwords.google.com/select/KeywordToolExternal

2. Microsoft: will tell you how likely the KW is to have a commercial intent
http://adlab.microsoft.com/Online-Commercial-Intention/Default.aspx

I use both on a daily basis. By the way, if you find a KW doesn't have much search traffic, it might make more sense to target it with an AdWords (i.e. PPC) campaign.

Put yourself in your buyer's or seller's shoes and think about what they may be searching for in Google. Using Google's keyword tool, run an initial search, perhaps like "Atlanta Homes." See what ideas populate. You want the highest traffic with the lowest competition possible for the fastest results. Take a few words from your initial search and then replace "Atlanta Homes" with those new terms to get even more ideas. Create pages around the words that you are targeting or make sure that your page is relevant to the terms you select. Blogging about such topics can help to promote your SEO for the chosen niches.