... I get around 300 visitors/day from google to my directory which is not even showing in the first 1000 serps for web directory. Is this normal?
what keywords / keyphrases are they getting there from? it's possible you're just getting long tail traffic.
check you log files and see the reference being made from google to your site. in the url you will see somthing like q=the keywords being used
You should sign up for Google Analytics and it would tell you where they came from what they did on your site, when they left, how much time they spent there, what pages they liked and whether they bought anything. Really COOL program.
300 Uniques isn't bad for a directory Are you sure you're not perhaps listed on a free directory list like vilesilencer?
there's nothing wrong with that. most people don't realize it, but long tail traffic is generally much more powerful and much more significant than ranking for "big" keyphrases. I just wrote an article about it
If you have awstat in your server you can check the keywords there where you were ranking. Also you can signup for Google Analytics account.
Keywords are extremely important, do some keyword research and place the most relevant into your articles.