To best discuss this topic, we must divide it into categories
1. Title Tags
The title should contain keywords and phrases that are important to your site. Our recommended maximum number of characters for this tag is 60 years.
Also when counting your characters remember that space is considered as well.
Titles should appeal to the reader otherwise even a top position will lose a lot of clicks.
For example, "shoes, Nike shoes, best shoes, review shoes," is unlikely to elicit a click. What can cause a click would be like: 
Shoe - Find out the latest styles on name brand shoes.
2. Description
The maximum number of characters that we recommend for this tag is 150 Longer than this and it will only be prevented and can be counted on your website is listed high in search engines. Try to repeat your keywords that you used in your title in a proper sentence and in 3rd party. Avoid I, Me, Myself, etc.
3. Keywords
Our recommended maximum number of characters for this tag is 250 Anyone can do more than it is considered spam. Keep your keywords focused on what your site is about.
Do not think that if we use an assortment of different keywords that your site will be a seller. Targeted marketing is associated with your keyword.
4. Keyword Nesting
Description: An expression used in the search to specify the order in which operations must be performed
Surrounding words in parentheses identifies a group or "nest." Groups can be within other groups.
The operations to be performed from the innermost nest to the outmost, and then from left to right.
Keyword nesting is nesting your top 5 most important keywords in the HTML page that the public will see. We would recommend using the keywords you used in your title, description.
5. Head Tags should not be confused with (head) tags def.
HEAD or HEADER (HTML document)
The upper part of the HTML source code behind Web pages, beginning with and ending with. It contains the title, description, Keywords fields and others that web authors can use to describe the page. The title appears in the title bar of most browsers, but the other fields can not be seen as part of the body of the page. To see the part of web pages in your browser, click View, Page Source. In Internet Explorer, click View, Source. Some search engines will get based on text in these areas.
Head Tags should be a repeat of your title tag. Most webmasters put their head tag right after the body tag. A head tag will look like this (h1) (/ h1) with (and) are replaced with <>.
6. Anchor Links
Anchor Links is one of the most important html tags that your site should win the search engine page rank especially in Google and MSN.
