To change key wordsin the html language there are special tag – meta. People viewing the web page, you will not see the contents of the meta tags, but search engines will see this content and recognize it. Meta tags are located in the part of document head. It looks like this:
A list of key words – these are all key wordsthat should be listed, separated by commas. It is recommended to do not more than 10-15. Search engines be sure to validate whether the site key words in the text. Therefore it is necessary to list only those wordsthat truly reflect the essence of the page. It's best to write your keywords for each page of your website.
Description of the site. You should keep in mind that search engines usually do not take the descriptions longer than 160 characters. So you need to keep within this limit.
If you set key words, breaking the rules of search engines, the site may be banned and he'll never appear in the samples of the search engines.
Key words, of course, not yet nominated your page on the first position in the selections of search engines for user queries, but when you do web site promotion is one of the most important steps, so it is worth spending time on it.