Using Single keywords in the titile or the post is an old tut.Now a days due to high no of search engines and knowlege people use phrases.The problem with good keywords is that they are usually not words at all. Good SEO keywords are usually phrases, that is, two or more words strung together in a saying or idea. When you enter keywords into your meta keywords section, don’t use words, use phrases.

Nobody searches for single keywords

Nowt hink when was last time you searched on google or on any other search engine with a single keyword you use phrases.

If you want to search for  blog help you will not just type blog help or help.You will use phrases and search as blogger help or wordpress help and type your required problem.
If that is how you search for relevant sites, then that is also how you should write and prepare your own pages and posts so others can find your sites.

There are too many single keywords

You have notify that when you are writing a post and you are writing a post on jquery plugin you will notice that there are other millions of website using the same keyword so you should use the keyword merged in a phrases like best jquery pugin for blogger or something else this could help you alot to be different from others.You significantly narrow the field of competitive websites, which allows your page to rise higher in Google Search results for that phrase.

The Best Places to Put Your Keyword

1.       Title Tag 

 Not to be confused with your "Page Title," the Title tag text shows up in several places including as the bolded blue text on Google Search Engine Results pages.

2.       Meta Description Tag 

Like the title tag, this tag is important because it appears on the Search Engine Results page right underneath the page title. Sometimes a snippet of your text will appear instead but you always want to have a meta description on every page and it's usually a good idea to customize it for each page.

3.      Page Title

 This is the actual page title your visitors will see when they visit the different pages of your site. Avoid using images, try to make your page titles text, include your keywords in them, and try to put them inside an H1 tag. This will give them greater SEO power.

4.      HTML vs. JavaScript 

Part of the SEO ranking calculation is how high up on the page do your keywords appear? Because of that, it's a good idea to take as much as possible of your JavaScript code out of your site's pages and put them in a single, common JavaScript file. This will make your site easier to maintain and boost it's SEO power.

5.      Keywords in Repeated Links 

Using your keywords in the links on your site is a great way to show their importance to search engines. In addition to doing this in your text another great place is in your sidebar or footer. 

6.      Alt Tags 

 Each image on your site has the ability to define "alternate" text. This is originally intended for Web site "reading" machines that read out Web pages to those who might have difficulty seeing the page. Instead of leaving the alt tags blank, fill them with descriptive text of the image that includes your keywords.

7.      Your Domain Name 

If you can get a domain name that uses a primary keyword this will give a big boost to your rankings. The implication is that this the entire content of your site is centered around this keyword.