A keyword is a term that you will place in your article several times. Where the keyword you choose will either be a word or phrase that captures the essence of your article.

There are 3 things to note when using keywords to increase your article's Search Engine Optimization (SEO):

Keyword Quality - How good is the keyword as a search term for your article

Keyword Density - How often your keyword appears in your article

Keyword Placement - Where you place your keyword in the article.

Keyword Quality

You want to choose keywords for your article that are relevant and targeted towards your reader. A good way to do this is to get into your reader's head . For example if you were writing an article about growing Bonsai Trees. Your target audience would be Bonsai Tree enthusiasts. You should then ask yourself what terms would they use to search for relevant content in a search engine. They may type "japanese tree", "bonsai tree", "growing a bonsai tree" just to name a few. But your task is to choose the ones that fit best for your topic.

A good way to find good keywords are to use keyword tools that are available online such as:

http://inventory.overture.com/d/searchinventory/suggestion/

http://freekeywords.wordtracker.com/

Look for a few keywords. Some will of-course be better than others. But also realize that phrases (i.e. more than 2 words) as keywords are probably better than single words, as single words have become too competitive as search terms.

Keyword Density

Keyword density is a statistic usually measured as a percentage. For instance, if you have written a 500 word article and have your keyword appear 25 times. You have achieved a keyword density of 5%. It is common for your article to possess a keyword density ranging from 3% to 5%. Having said that you could probably find hundreds of different blogs and guides recommending different densities. You will have to choose what level churns out the most profit from your articles.

But do note that "stuffing" your article with excessive keywords lead to poorly written articles that make little sense. And more importantly can lead to penalties from search engines for repeat and serious offenders. If in doubt, just keep it to 3% to 5%.

Keyword Placement

The most important place to put your keyword is in the article's title. Following which you should structure your article resembling the image of an hour glass. Where the bulk of your keyword terms or phrases are placed at the beginning and at the end of your article.

For example you would start with an introductory paragraph bulked up with your top keywords. Following which you would spread your weaker keywords throughout the main body. Ultimately you would conclude your article with your closing remarks, again trying to bulk it up with your top keywords.

Optimizing your article with keywords to rank higher in search engines is a vital strategy for you to employ. This will help improve article marketing efforts to drive targeted traffic to your website. But do note that although SEO for your article's are important and is something you should do. Do not become obsessive and plan your article around fitting and stringing in as many top keywords as possible. Just remember in the end readers are looking for good quality content that deliver value.