You've probably heard about how Facebook has been reducing the number of followers who see posts published by companies or brands.

An analysis by PR firm Ogilvy & Mather found that companies' Facebook posts dropped from reaching 12 percent of their followers (already a super low number) to just 6 percent over just a few months.

My email marketing company VerticalResponse has seen a sharp decline in the number of people viewing our organic Facebook content. Maybe you've experienced the same, too.

The message from Facebook is pretty clear: Open up your pocketbooks, or your content won't reach your followers. That's right, you've got to pay to play.

The good news is you don't have to spend an arm and a leg on Facebook advertising. In fact, it can be pretty darn affordable and effective if you start with clear goals and direction. Here are four things to think about before diving in:

1. What results do I want?

Get more "likes" for your page? More views and engagement for your posts? More clicks to your website? More people to claim an offer? The Facebook ad platform offers several different options to choose from. Or you can run multiple campaigns at the same time to impact your business even more.

2. Where do I want my ad to appear?

On Facebook, ads appear either on the right-hand side column or within the news feed. Both have their pros and cons. The ads on the right-hand side feel less intrusive, but people are more likely to ignore them altogether because they know it's advertising. You're more likely to get exposure if your content is placed within the news feed, but you run the risk of annoying people who might find it too intrusive, especially if it's a sponsored post (a paid post that can be shown to people who've never engaged with you).

Our efforts here at VerticalResponse have shown that you may obtain less clicks from the ads in the news feed, but they tend to be more likely to convert compared to their right-hand side column counterpart. Test both options and see what works best for your business to make sure you are effectively using your budget.

3. How do I want the ad to look?

Keep in mind that for ads in the news feed, text can't take up more than 20 percent of the photo. So your image or photo should be powerful and compelling. Also remember that if you use the news feed option, you get to choose a call-to-action button, like "sign up" or "shop now." A news feed ad also provides an extra 200-character link description, where you could clarify your product or service even more.

4. How much do I want to spend?

You can choose either a daily or lifetime budget, and whether you want to pay for specific actions (for every "like," for example) or per 1,000 impressions. Keep in mind that an "impression" doesn't necessarily mean an eyeball on your ad; it just means it appeared on someone's page. Also remember if you use the lifetime budget option with a very small dollar amount over an extended period of time, you might get less than stellar results. There might not be enough impressions of your ad to be clicked on at the level you would expect.

If you've run a Facebook ad campaign for your biz, what worked and what didn't? Let me know in the comments below.

If you enjoyed this post, sign up for the free VR Buzz and check out the VerticalResponse Marketing Blog.