One of the best things you can do for your site is write genuine content articles.  Basically the simple principle here is you want to write content other users will read and link others to.  How do you write SEO friendly articles though.  Here are a few tips.

Use the proper heading tags for your content article

The tilte should always be in heading 1 tags aka h1.  Find out more in this article PhpNuke Article Titles and the use of Headings.  The subtitles should follow in heading sequence such as h2 through h6.

Research Your Topic

Any information provided should be relevant and up to date.  Yeah this is maybe the hardest part.  You have to research your subject unless you consider yourself an expert.  Then it is still a good idea to read some more.

Don't use Click Here as your link text. 

A person wants to know where they are going when they click a link.  So if you use the anchor text "Click Here" and it takes me to a page I thought was something else.  Odds are I am leaving your site and have no intentions of reading the rest or your future articles.  Instead use the relevant title for the page or article your linking too.    For Non-Human visitors (search engines) using the proper link text gives them something better to reference the source.  If you had a mass of  links to your site with the anchor text "Click Here" you would most likely have the #1 position in google for that term.  Instead you want to use a relevant title for your anchor text.  Even if your interlinking to your own pages on your site.

Here is a short Definition from Aaron Wall's SEO Glossary for the word "anchor text".

The text that a user would click on to follow a link. In the case the link is an image the image alt attribute may act in the place of anchor text.  Search engines assume that your page is authoritative for the words that people include in links pointing at your site. When links occur naturally they typically have a wide array of anchor text combinations. Too much similar anchor text may be a considered a sign of manipulation, and thus discounted or filtered. Make sure when you are building links that you control that you try to mix up your anchor text.

   
    Bad Link
       Click Here

   Good Link
         PhpNuke Article Titles and the use of Headings
   

Use quality keywords (using one keyword more than 10-15 times could be considered spam by the search engines so be careful)

Using quality keywords doesn't mean packing the article with the same keyword over and over again.  This could be considered spam and is a well known grey hat SEO technique.  Such an action could easily result in search engine penalization.  The best tactic is to pick 4 to 5 words and use them as often as possible without exceeding a safe limit of 8 times per word.  Also remember your writing articles for human users so the article and its format should be easy to follow.  I never seen a person watching TV continue to watch a bad commercial.  They always change the channel.  The same theory could applied to your article.

Linking your sources the wrong way and the proper way

Be sure you link to your sources first off.  This technique is great for the users because they may want to continue reading about a specific part of your article and its great for search engines especially if your linking to a trusted source such as Wikipedia or Google.  Even if it had no actual benefit to your article or the way it reads.  Its simply good practice to get in the habit of.

My personal preference for linking to others is to use my link in a sentence versus adding the source to the bottom of the page.  The reason for me is its easier to read and makes more sense.

Example
Just a few days ago I was reading a blog on Aaron Wall's SeoBook.com about link perception ,Link Quality: Perception is Reality.



Those are some simple steps to writing good articles.  I can't reinforce this concept enough for young web site owners.  I hope this was helpful.