You can join the fan pages that related to your page, send them message privately..please don't spamming..
This is the best piece of advice I've heard so far. Indeed the human factor is the most important factor. I just corresponded with this cartoonist on facebook and he explained to me politely why he needed more fans and he really aroused my goodwill, with his politeness. Usually these kinds of requests irritate me and I ignore them.
Yup that is the point! be polite peoples will love you, send them message nicely believe it or not in return peoples will keep in touch with you nicely too
Make as many friends as you possibly can and invite then all to join your page. Writing something personal along with the invite goes a long way as well.
Now wordpress base site have extra advantage because come out Facebook plugin, just install the plugin then your reader easily like your post to shared with others.
Now from this info, I now see how those fan pages acquire thousands of fans and maybe they use this, Somehow I think I should use it too for my own advantage not just today but for the long run.