Doctype means a "document type declaration" (DTD). All HTML and XHTML pages should use a element to define which HTML version it conforms to. The doctype defines which version of HTML you are using, and gives important information to your browser so it can render your page faster and more consistently. The doctype declaration also allows validating software to check the syntax of your page:

The <title> element is one of the most important HTML elements. Its main function is to describe the content of a web page.

Even if title is not visible part of the web page, it is important to the quality of the web site because it is visible in the following

The title must be short and descriptive as possible. When the user searches an internet for the web sites, most of the search engines do display the title of web site in the search result. Make sure that the title should match the content user is looking for. Then only the user will click on the link to visit your web site.

When a user is visiting the website, title will be visible in the windows title bar. Make sure that the title describes the site even when a window is been minimized. After when user has visited the website, the title of the web pages will be stored in the visitors history folder (or in his favorites folder). Do make sure that the title clearly describes a pages for future visit.

An <h1> element is used to describe a top level header of the web page. Since some of the web browsers do display <h1> element in a large font by default, some of the web developers do use a <h2> element instead of <h1> element for the top level headers. This will not confuse reader, if he is person, but it do confuse most of the search engines and the other software which will try to "understand" a structure of web page.

Make sure that you use <h1> for the top level headers, <h2> and <h3> for the lower levels. Try to structure the web page headers after this template: