1) Buy ads. You can target your cause very specifically on Facebook. Then add pay per click, just like you would do on Google. BlitzLocal recommends a small ad budget, but using Google Grants as a primary vehicle to drive people to your website is a great idea. Then have a 'like' box there.
2) Get a 'like' box on your site. If you hit "edit page" and go to the bottom right, you will see an option for "promote with a like box." Grab the code there and paste it into your site.
3) Create a contest. As a condition of winning the prize, whatever it may be, require that fans write a comment of at least 30 words on why they deserve to win or whatever. For them to comment, they have to like the page.
4) Incentivized like tab. This is advanced stuff for programmers only. So if you know someone who understands FBML (or ask kindly and perhaps we will do it for you), you create a landing page that reveals the content behind it only if they click like. Think of it like a scratch off ticket. So have something attractive enough to stimulate action. See example here for Grameen Foundation.
5) Let your users participate. Most fan pages allow post by page only,which is the default option. Change that setting to "posts by pages and fans." When people know they are allowed to participate, they will; their participation, in turn, notifies their friends' notifications, which, in turn, bring those friends in.
6) Send a Facebook message. Little known option, but when you click "edit page", you can send a message to fans. This generates a real email, not a Facebook message. Whatever you do with your regular email program, so it will with Facebook.
7) Interact with users. Not just because it's the polite thing to do, but because it increases your Post Quality Score, which then increases your prominence on the walls of your page's fans. When you or a fan makes a comment or hits "like", only a portion of friends will see it. That percentage is governed by how much interaction Facebook sees.
8) Choose a custom url. Go to Facebook.com/username to choose a url for your page. The option is available once you get to 25 fans. A short url is better than a numerical monstrosity, making it easier for fans to remember you and find you.
9) Mention your Facebook page in your other marketing efforts. The custom url helps. Place the url in your email signature line, business cards, brochures- even paint it on the side of your minivan! Print sticker with your logo and Facebook url below.
10) Cross-promote with sister organizations and those who endorse you. Did you know that pages can become fans of each other? Don't go crazy here doing link farms and chains, but you might as well get every advantage you can get.
11) Update your Facebook page with your twitter and rss feeds (blog posts). We believe that if you post content once, it should be available everywhere. We are too lazy to have to manaually copy content to 15 other sites, so we use easy plugins and apps to do that. Likewise, meet users where they are, by making it convenient for them.
12) Get popular people to mention you on their wall. Did you know that if you post the full url of your page (which includes the http part), then it creates not only a blue clickable link, but also shows how many fans the page has? More fans means you look more popular, which means more people will check out what's there.
13) Automatically invite all your friends: you aren't actually clicking on every single friend you have when you hit "suggest to friends are you? Check out this article for a clever trick.
14) Say things that are controversial. Don't be inflammatory or rude, but do pose charged issues that will bait people into expressing their opinion, thereby drawing people in. You might even seed the discussion or wall post by arranging in advance what side each of your team members will say, just to get things started.