No one can tell you the exact formulate to make SEO work perfectly. It is a constantly evolving subject and as a result it has spawned quite a few myths. Here are some of them.
1. Keyword density – It was true that at one point keyword density mattered a lot. Keyword density basically meant that you had to have a certain ratio of key words to the amount of words on the webpage. But now none of the big search engines place much weight on this factor so you are free to write in any style that you wish.
2. Submit it everywhere – People used to believe that their URL had to be submitted to every single search engine there was. In fact there were and there still are some services that offer to do this for you. In reality, there are only three search engine you need to care about – Google, Yahoo and Bing. These three have the most market share and are the most sought after.
3. Page rank is god – It is not. While page rank plays an important role, it is not the be all and end all of all things SEO. There are many other factors that go into bringing your page to the top of a search result. Work on those and do not worry about getting big PR in the short term.
4. Meta tags – Although they help a little bit, they do not do the magical thing that they are supposed to, which is push you straight to the top. Use the meta tag wisely and lower your expectations.
5. SEO needs to done only once – If you believe this, you might as well quit the business. SEO is a constant operation that needs to be performed on your site. Do not do it once and sit back and wait, you will have wasted your time.