1. Alexa Traffic, the most basic step: Get lots of site traffic! Because the initial idea of the Alexa rank is to determine which website has the most traffic with the assumption, more traffic = more popular. Yes, Alexa is essentially a popularity ranking of a website.
2. Alexa Toolbar, Using a browser that Alexa toolbar installed can ningkatin your website ranking. Actually, not just your website, every website visited that Alexa toolbar installed browsers also gets "value" to be taken into account in the ranking. Then, is not sure of your website visitors is yourself? So, if your browser already installed the toolbar, then the addition of ranking points will occur automatically.