The lower your Alexa score, the more popular your website is. i.e. Google is number 1 and an unknown website is 12,543,456
Also, I would like to know why you would want to REDUCE your alexa ranking. or are you speaking of making the alexa ranking number smaller....so it is is seen as a more important site? Please answer and I can advise.
social bookmarking and directory submission. you may also want to submit press releases relevant to your latest blog post. at least submit a press release once a week and you're going up the rankings in no time.