These days SEO is more of a professional practice now than any time in the past. In the past, SEO was nothing more than simple Google bombing. Nowadays you have to pay attention and spend much hours reading SEO forums and articles to understand search engine optimization.
There is lot of SEO commentary, but the essentials are sometimes overlooked. Here are the top ten SEO mistakes to avoid mention by Peter Da Vanzo -
1. No Marketing Plan - if you don�t know who your market is, and what they want, rankings will not help you. They�ll just help chew bandwidth and raise your opportunity cost.
2. Selecting Keyword Terms Based Only On Traffic Volume - you need to be number #1 for �cars�, because the term �cars� recieves a lot of search queries and you sell �cars�? That won�t do you a lot of good if you only sell cars in Fiji. See #1.
3. Selecting Keyword Terms That Have Little To Do With Your Service - the days of drag-net SEO using off-topic keyword terms are long gone. Be specific. If you sell cars in Fiji, you want �car dealers Fiji�, and semantic variations thereof.
4. Failure To Use Keywords Your Market Is Actually Using - the copywriting printed in your corporate brochure isn�t how your customers speak. It certainly isn�t the way they phrase search queries. Listen to how customers ask for your goods and services. Those are your keyword terms. Find variations of these terms using keyword research tools.
5. Thinking All Search Engines Are The Same - they�re not. What pleases Yahoo! and MSN does not necessarily please Google. If your audience uses MSN, then work out what MSN wants and deliver it. The solutions can be complex and varied, depending on how�cough�determined you are, however, if you want to hit a middle ground, they all tend to like keywords in the links (at the time of writing).
6. Relying on Keyword Density - a redundant technique. Instead, stay on-topic and incorporate your keyword terms. How often do you use them? If you read your copy aloud, and it sounds odd, you�ve overdone it.
7. Poor Titles - When a visitor looks at a SERP, they have 10 or more choices. Think of titles like newspaper headlines. Repeat the search keyword term and make the title enticing. Think Adwords. In fact, look at how the Adwords advertisers have written their ads for your chosen keyword terms. Chances are, those Adwords on the top have high click-thru rates. They�ve got their titles right.
8. Not Getting Links - links are really important. Really. Really, links are really important. Did I mention that links are important? Link aquisition is essential strategy. Depending on your area, you probably don�t need many, but you do need some.
9. Thinking That Hacking Code Will Solve All Problems - For most sites, advanced SEO trickery isn�t necessary. Stick to the search engine guidelines, keep your visitor in mind, write like they speak, ensure your site can be crawled, network in your space, get links. Repeat.
10. Not Thinking Beyond SEO - After a visitor arrives, what then? If you�re not serving their needs after they arrive, then your SEO effort and expense has been wasted. See #1.
Good SEO has a lot in common with good marketing 
