I have the best results from a structure like this:

Keyword Phrase - 3 Things You Need To Know About Keyword Phrase

The keyword in the first, or introductory paragraph and no more than 2% total for article.

Keyword anchor in resource box.

With Articles: The Importance Of Keywords

Keyword density and placement are important parts of optimizing your articles for search engines. Search engine spiders scan a page in a way that makes it important to place your keywords where they will be detected and recognized as a keyword, so that your article will come up when someone searches for that keyword.

What is a Keyword?

A keyword is a word that is going to be placed in your article several times, not just once as that would make every word a keyword. When a spider sees that you have a word placed several times in an article, it will determine that your page may be useful to users that search for such a keyword.

Over Optimizing Your Articles

It is important to note that there is also such a thing as over optimizing your articles for particular words, this is known as "keyword stuffing". When you stuff keywords in an article a spider will detect that you are trying to trick it into placing your article high in the search engine results for that word, and will instead penalize your site and your page for doing such. This may even affect the rankings of your other pages or get your site blacklisted from a particular search engine if you are found keyword stuffing too many times.

What is Keyword Density?

Keyword density is how many times your keyword is placed in your article. Most use a percentage to determine how many times they will put a keyword in an article. For instance, if you have a 500 word article and want to achieve a keyword density of 5%, then you will need to have the keyword in your article exactly 25 times. You can find hundreds of resources and guides recommending one keyword density over another and the reasons behind the logic, however, in the end you will have to determine which density is more profitable for your articles. Each webmaster as their own density that they like to achieve based on past results. As long as you don't over optimize and you are making sufficient profit from your rankings, then you can choose whatever keyword density you like.

The Right Density

No matter what exact density you choose, it is important to place keywords so that there are more at the beginning and end to produce an hour glass effect. Having the right keyword density in your article makes it more likely that you will make money off of that article because it will rise in the search engine results and be seen by more people.

[DELETED]

this is call keywords solidarity and i read about it here

Title starts with keyword, keyword in the first sentence, twice in the first paragraph if possible, keyword in last paragraph and sentence, keyword anchor text, and overall 3-5% keyword density. Those are the guidelines I use.

Although you want your keyword to feature prominently in your article, you also want your article to make sense and read well. I can't imagine an article with 50% keyword density (keyword every second word!) making any sense! I don't think you would get a good clickthrough rate with an article like that.

I use keyword in the title, first paragraph and in some parts of the body of my articles. I also include the keyword in the anchor text of my resource box.
Keywords - around 2%.
I use this to all of my contents

I put keytwords in title, keyword and descriptions. then the body is about 2-5 % density.

try putting LSI keywords in as well, I go for 2-3% keyword density, then checkout google wonder wheel for my lsi keyword phrases. Finally, I send a few social bookmarks, submit it to rss directories and other links to the article to give it a bit extra oomph.

Hi!

From my studies and experience, your keyword should be found in your title, your first sentence, the middle of your article and at the end. If you put it in more than that, the search engines are turned off by the overkill of the keyword use. Be sure to research your keywords at adwords google keyword tool and chose words and phrases that are not overly used already. A good range is from 700 to 3000 searches for keywords you can use.

Thank you all for all of your thoughtful and interesting suggestions. This has been a tremendous help in my article writing.

cbondcarolina

The reason that I stay at or below 2% keyword density is because that is the limit that EzineArticles puts on an article for acceptance.

While there are other directories that are starting to compete with EA, I still believe it is one of the important directories to be in.

I started testing this with other forms of content like blog posts and simple html "mini-sites" and have found that the 2% density did better.

My thinking was that EzineArticles relies heavily on Google for revenue and if Google wants your article at EA at 2%, then Google would probably want that across the board.

So far, for me anyway, 2% seems to be the magic number.

Matt