You can separate your business marketing messages from your other content by using Facebook fan page tabs. People like to buy things without feeling like they are coerced into buying something. If you have the sales page within reach, people will be able to click on it only if they want to.
Don't stray far from the topic at hand when you post on your Facebook page. If you sell toaster waffles, you can talk about changes in tax rates. Posting some links to parodies of Harlem Shake is really off-topic and can bore or irritate your followers.
There are quite a few apps you can use with your company's Facebook profile which makes it more valuable. EasyPromos is a valuable application that allows you to put promos on your Facebook page.
Do not share facebook Update tool too frequently. This lets you send messages to be sent to every one of your followers. You should use this when it's most important. Facebook Statuses. This should not be used for simple promotions but as a continuous basis.
Try out some Facebook ads. Posting to your page will only goes so far. If you want big results, purchasing Facebook ads is the way to go. They cost very little and can help.
You want to have fans who are likely to purchase your products or share the content you post. Look at your conversion rate to get an idea of how well your campaign is.