Search Engine Optimisation

Search Engine Optimisation (or SEO) is the way you design your website optimally for seach engines (sounds obvious now, right?).
It includes mainly things like keywords and other 'meta tags' that I will go on to explain.

When someone at home types some words into search engines like Google, Bing or Yahoo! the search engines' 'bots' as we like to call them, search through the meta tags in your website coding to check if any of the keywords match and prioritise the results accordingly, depending on how many keywords match.
Also, the description meta tag is displayed on a search result underneath the title. The picture below shows which part of a search result links to which type of meta tag:

Simple as that really. Choosing the right text to put in a description is key, not too long so it doesn't fit, but long enough to give a potential customer the right idea of the websites' aims.

When a search engine trawls through your website, it picks out certain elements. One of the main things are 'header' tags. In HTML code, they are seen as <h1> or <h2> up to <h6>. These are ultimately different priority levels of headings, that affects the font size to start with (although this can be changed with CSS styling).
When a search engine sees a 'h1' tag, it sees this as, basically, a keyword. So when someone types something in to be searched, if something in your 'h1' tag matches, your website could potentially appear high up in the results. This is why it is important to use heading tags to outline certain words or titles on your website.

A meta keyword tag does the same job, however this defines a general set of keywords for the page you add them to.

This link should take you to a PDF document by Google outlining good SEO techniques. I will use this to my advantage when creating my website.