Create a custom Welcome landing page in Facebook so when people visit they are strongly encourage to click the Like button. See http://facebook.com/MariSmith for a great example of this.
Invite your existing Facebook friends to like your page (become fans), and hopefully they, in turn, will get others to also like your page and become fans.
Include a Facebook badge or link to your Facebook Fan page on your website/blog and in any email newsletters you send out.
Include a link to "Like" your Facebook Fan page in your email signature.
While you can only have one link in your Twitter profile, by creating a custom background image for your Twitter profile, you can display the URL for your Facebook fan page. See an example on this Twitter profile in the left column. Best if you've already created a custom URL for your Facebook Fan page (have at least 25 fans).
You can advertise with Facebook ads encouraging people to “Like” your Fan page. In line with that, you can consider offering incentives for people to become your Facebook fans, such as coupons, free downloads, etc.
You can send a link to your Facebook fan page to your new followers in Twitter and can occasionally Tweet out a link to your page inviting people from Twitter to connect with you on Facebook.
Include your Facebook Fan page URL on your business cards, brochures and stationery. Again, best if you've already created a custom URL for your Facebook Fan page (have at least 25 fans).