So what does making a site "friendly" mean? Well, basically it means using the right keywords in the right places. For example if you have a page about the Yashica 124, don't title it "Old TLR cameras", or worse not title it at all! Title it "Yashica 124 information". Then have a heading between H1 tags that says "The Yashica 124". Put "Yashica 124" in the alt tags on all the images on the page. Use the phrase "Yashica 124" rather than "the camera" in the text. Make it easy for a search engine to figure out what the main theme of your page is and it's much more likely to appear when someone searches for "Yashica 124". It doesn't hurt to make the filename "yashica_124.html" either, rather than "page23.html".
There are many tricks to the search engine optimization of web pages, and there are many websites out there that will give (or sell) you advice on the best way to do it. The purpose of this page is to make you aware that it's something you should think about right from the start of your website design. Use meaningful file and directory names and emphasize the use of major keywords when writing content.
HTML allows the use of META tags for content and keywords. META tags are used to define text which isn't actually used to create the web page. They're like "notes" which are attached to the page which web based software (such as search engine spiders) can see but which are not visible to the viewer. In theory this is great as it allows you to make a list of all the important keywords that you'd like to be associated with your site. However major search engines like Google no longer use the META tags when indexing websites. That's probably because a lot of sites have abused them by inserting popular keywords and search terms bearing no relation to what was actually on the web page, simply in order to try to boost search engine ratings. Google does however often use the META tags for content to describe your website, so pay some attention to that field.
You also need to submit your website to search engines rather than just hope they will find it. You can submit a list of pages to both Google and Yahoo. These lists are known as "Sitemaps". You can find out about Sitemaps at http://en.wikipedia.org/wiki/Sitemaps