Search engine optimisation is pretty much part and parcel of creating websites these days. Getting the basics right don't require a large amount of work, but can make all the difference. Many of these also improve the general usability and accessibility of your site too - so you get three major benefits rolled into one.
The points below are just a few basics I've picked up along the way; roughly in order of my own priority, relating specifically to technical changes you can make on your own site, regardless of any incoming links, frequency of page updates, or link building you may do; I'm not claiming this is a comprehensive list by any means - but I'd be very interested to from others as to what they've found.
1. It's all about the page title!
If you can't spare time to do anything else, at least do this! Ensure there is a unique title for each page on your site, and make it as keyword rich, and relevant to the content on the page as you can. If you always include, say, a company name and tagline in the page title, that's great - but it's generally a good idea to ensure the portion relevant to the page appears first. Seach engines truncate the titles, so it makes sense to have the most relevant and useful information at the start - and the consistent company name and tagline at the end - for both users scrolling through pages of results, and for the engines themselves.
2. Think about the text being used to link to pages
We've all seen Google "bombing" in action - the most famous being "miserable failure" taking you straight off to the white house. Interestingly, Google has now pulled the plug on that particular quirk. However, the general rule remains the same - if a search engine picks up a link with the text "great .NET products", even if the page itself doesn't mention those particular keywords, you can still be listed in those search results.
If you find yourself creating a bunch of hyperlinks along the lines of "Find more here", "more information", "click here" - you're wasting a potential goldmine of keywords, and from an accessibility angle, each distinct URL linked to from a page should have distinct text associated with it anyway . Think twice as to whether you can include some more relevant keywords in the link text, such as "Find more developer jobs here".
3. Be careful with images. Use CSS Image Replacement
Everyone by now is (hopefully) always setting the "alt" tag on any images they include on a page. However, search engines still treat these differently to straightforward HTML on the page. Following on from point #2 above,
<a href="graphics-card.aspx">Our Graphics Cards</a>
is generally weighted much more than
<a href="graphics-card.aspx"><img alt="Our Graphics Cards" src="graphics.gif" /></a>
If there are images on your site that aren't content in themselves (such as navigational links and headers), then you should be using a CSS Image replacement technique. This allows to you do something like this:
<a id="graphics_cards" href="graphics-card.aspx">Our Graphics Cards</a>
/* css */
#graphics_cards{
display: block;
text-indent: -5000px;
background: url(graphics.gif);
height: 25px;
width: 25px;
}
This technique can (and should!) be applied to headers too, if you're using images there.
4. If you must use flash, put some text in too
Using something like SWFObject allows you to embed a flash movie, but also include a HTML equivalent that will be indexed by search engines, and viewable by users with flash or javascript disabled.
6. Ensure content is accessible via hyperlink (watch out for AJAX!)
Sounds simple, but if you're using any sort of form submission (such as a drop down box) or ajax-style scripts to navigate to content on your site, then your content is not going to be indexed unless you take a few further steps.
a) Ensure the content can be accessed directly from a distinct URL too (ideally in conjunction with url rewriting - see point #7). If you've got a drop down box listing frequently asked questions, when an item is selected, redirect the user to a unique url for that FAQ entry, rather than just post-ing back and adjusting the content of the page.
b) Ensure you've actually got links pointing to these distinct URLs (whether within elsewhere on the site, or externally). You could also use a Google SiteMap so that at the very least the search engine knows those pages exist.
5. Page descriptions
These are often displayed in search engines if the keywords have matched a page title rather than its content - so they're worth including even for this - and they still seem to be used for picking up relevant keywords too. Once again, the same points apply as in #1 - don't just re-use the same standard page description across the entire site.
7. Deep linking
This is harking back to point #2. If you publish articles, press releases, or the like on your site, and it mentions a product, or another article on the site, then make sure it links to it! This increases the number of contextually relevant links and possible keywords that a search engine might associate your pages with, even if these links are just internal.
8. Use URL rewriting
There are loads of URL rewriting techniques out there. Sensible use of URLs increase the usability of your site, and also allows the search engines to pick up on keywords in your URL too. In order of improvement:
http://www.mycompany.com/page.aspx?id=29&page=ingredients (worst case)
http://www.mycompany.com/product-information.aspx?id=29&page=ingredients (at least give the page a meaningful name!)
http://www.mycompany.com/product-information/29/ingredients/ (search engines still don't like query strings all that much)
http://www.mycompany.com/products/chips/french-fries/ingredients/
The final example is logical, "hackable" (the user can guess that /products/chips/ will take them back to a sensible page), and keyword rich. Note that the URL of this blog entry follows these lines too!
9. Unknowns...
Things I'm not 100% sure about.
- Keywords meta tag. I've deliberately not mentioned this here, as I've seen no sign that these are being used any more.
- Order of content on the page. I always try to ensure that the main body of the content appears as high up the page as possible. This has accessibility benefits (so a screen reader doesn't read the same set of navigation at the start every time a page loads), but I'm not sure how much weight a search engine places on this order, or how large the page has to be for this to make a difference.
I'd be interested to hear if anyone has suggestions of other must-do's that I've missed.