This FAQ explains the basics of optimising your web site before you submit it to the search engines. This is not an exhaustive FAQ but rather just to help you on your way.
The best time to do this is before you have the content on your site as it saves a lot of time going through and changing the wording. Whether you already have the site up or not, before you start you should decide what keywords you want to optimise for, use words that are likely to be searched for and ones that are not going to be used by every site on the net.
Lets take the following sentance for example..
Welcome to Tek-Tips.
You could change this to:
Welcome to Tek-Tips, a very large collection of free technical work forums used by computer professionals to discuss and resolve various technical issues.
Both are virtually telling the same thing but in the second you have included keywords that are relevant to the content of your site and it also looks more appealing to a visitor.
The main thing to remember is that you want to keep the visitors after they arrive at your site so do not flood your pages with keywords just for the sake of it, make sure that your site still makes complete sense when you read it.
In your title tag, include the most important keywords and use as many as you can but still keeping it short.
Same goes for your description and keyword meta's. Put the keywords in order of importance, some engines only read a certain amount and then ignore the rest, so do not put the following.
Now, if an engine only reads the first 5 keywords, then it has read the most important ones.
For all 3 (Keywords, desc and title) include your most relevant keywords in all of them as many times as you can but again, do not go overboard as too many in your keywords for example will likely lower your rating without your knowledge.
Just go through your site and work out where you can include more keywords and then make sure you double check that the phrase still makes sense.
Also, use your alt tags and title tags to include keywords, but keep it short and relevant. One thing I really despise is a site that when I mouseover an image I get about 300 keywords popping up in the alt tag.. (Very unprofessional)