Submitting to blog directories is one of the method to drive traffic to your site. It will take some time cause it is review manually by human and don't forget a lot of people are doing the same thing like you.

That's why you need to use other method as well so that you can get traffic from different channel. Either you use free or paid method.

For paid method, the most popular method is pay per click. Other alternative is media buy or banner ads.

There are a lot of free method that you can use:
-Forum posting like what you are doing now
-Blog commenting.Put some comments on other's people blog
-Submit RSS feeds to RSS feeds directories
-Social networking sites like Facebook, Twitter and so on....
-Link exchange

and many more......