Join in the WP plugin conversations on Twitter. Follow @yoast and the people that follow him and engage them in meaningful conversation - make sure your Twitter profile is built for your business and not just your social life.
I assume you've already made it available to the WP Plugin community on wordpress.org.
Contact WP Theme builders. Ask if they might review your plugin. Monitor the WP forums and get to know the people there. If you develop relationships with some of the people there, then you might be able to ask them to review it. Be careful - no one likes to be marketed to, especially if you've only just met them. Be patient and respectful.
[edited by: lorax at 3:35 am (utc) on Dec 23, 2012]
Firstly improve your README.TXT, because when people look for plugin they see the README File. Second thing is Create a Plugin Website. It is the best way to popularize it. Create Videos and Screen Shots, then Maintain the Plugin, Documentation etc.