Psst. Here's a secret. If you want a lot of fans quickly you need one of two things: Money for an ad buy or an existing database (think your email list) that you can easily convert to fans. If you don't have either then your best bet is to grow organically, by providing interesting quality content in your wall posts. Sure you can offer a giveaway, but even a giveaway without a large fan base and advertising support will only draw in so much activity.
Don't get me wrong, there is nothing wrong with growing slow and steady, just make sure your expectations are set correctly.
If you have a page that has under 500 fans - expect to grow somewhere between 5 - 15 fans a month. 2,000 fans you could up it to 30 - 50 new fans/month. 30,000 a fair bet is 1,000 - 2,000 new fans/month. These are rough estimates but should give you some guidance.
Don't beat yourself up if you aren't pulling in thousands of new fans each month. Slow and steady isn't a bad way to go, especially if you are getting the right people and your engagement rates are high.
So next time you get pulled into a meeting and the boss man wants to hit 1 million fans in two months, it's best to be upfront and tell him or her to budget some $$ for advertising. That's just the way it works.