There is a lot to know in the world of SEO.
SEO is an interesting beast that changes and shifts so often it's hard to keep up. The reason being, Google controls how their search engine works so if they change the way they index info on the Internet, you have to change the way you optimize it.
That being said, Google still indexes importance by popularity. If your site gets more hits than another, the information must be better because people keep coming back, right? Whether or not that's right, that's how Google does it.
What if your page isn't that popular? Well, then you can apply some of the simple SEO guidelines from the first link on this post. SEOMoz is great for helping you understand exactly what SEO is, how it works and how your business can take advantage of it. The better indexed your website is, the easier it is for potential customers to find it. The more people that find it, the higher chance you have of people buying your product. That's what SEO is all about.
The best thing about SEO is that it's FREE! You don't have to buy ad space or pay to run a campaign. All you have to do is fine tune and customize your website and Google will index it for free. This is one of the reasons SEO is so important for small businesses. If you are good enough getting your content ranked higher on Google, you can get free search traffic just because you show up in more people's results.
SEO is not going anywhere. It will only become more important. Social media is starting to make an impact on SEO now as well. For example, if you have a Google+ page for your business, you will automatically rank higher on search results and you can see who of your friends already like that business when you search. Twitter is also in the mix. Your Twitter account shows up in search results so having a well optimized name and description could give you an extra boost in the SEO world.
Have you ever had any experience with SEO? What kinds of things have you found that work and don't work?