Search Engine Optimisation is a term that is thrown around by a lot recently with out people really understanding it. Many web developers will claim to be able to get you a google page rank of less than ten but you need to think about what the search term is and how many other web sites are competing for that page ranking. You also need to consider that there are many many variables a user can enter as a search term when looking for your products. As an example lets consider a website made for XYZ123 Widgets that makes red and blue widgets. Obtaining a high ranking for XYZ123 Widgets is fairly achievable as the search term fairly unique. On the other hand obtaining a high page ranking for a search term such as 'Widgets' or 'Red Widgets' is a lot more difficult.
There are 4 main areas to consider.
Meta Tags
These days META tags are the most least used item for search engine robots. All Meta Tags do is state what your website "claims" to be about, and search engine indexing won't just believe it blindly. Meta Tags are also subject to the most abuse by the unwary and incorrect or inappropriate meta tags will harm your ranking. In these days of smart search robots meta tags should be concise and accurate.
Valid Markup
Ensuring your site is valid HTML or XHTML with no errors and all content accessible as text to the google robot. For example if using Flash have a flash alternative provided and ensure that the ALT tags for images are accurate. Using inappropriate ALT tags, secretly hidden text and other misuses can and do actually harm your ranking.
High Quality Content
Your content should try to be original and make use of your key search terms as much as possible. A site optimised for "NRL" might have text like "Welcome to Mike's NRL homepage, any and all NRL related news, NRL highlights and NRL results can be found here." This is a really simple example, but as you can see its not simply a matter of just adding the meta tags. Things like poor spelling hurt also.
High Quality links
Probably the most important consideration is to have high quality links. That is to have people from high quality, highly ranked/popular websites have links directly to your site. This is possibly the hardest to acheive and is also the reason why many spammers will target online forums and blogs etc with inappropriate links. Initially you can try submitting your webpage to various directories that will provide links to your page, albeight low quality ones, but more is better than none but make sure the directories you submit to are genuine. Sites set up simply as "Link farms" to promote page rankings can have a detrimental effect on your page ranking.