Meta tags are snippets of text which are encoded in the structure of web pages and provide search engines with information about that web page and about the website. The most important of these tags are the Title tag and the Description tag.
Title Tag
The title tag as the name suggests gives the heading of the page and is therefore given an important status by search engine algorithms in matching results with keyword searches. Title should be kept short and snappy and should include keywords that the the website owner wishes that page to rank highly for. Ideally the length should be between 50 and 55 characters in length as Google typically returns between 50 and 60 characters in it’s title displays.
The title of a page should be as descriptive as possible and should be different for each page of the website. The title should be reflected in the content of the page, maybe as a H1 tag near the top of the page.
Description Tag
The meta description tag is the second most important meta tag. This provides the snippet of text under the title in the search engine results. This can be longer than the title but should not be more than 160 characters in total to avoid truncation when displayed. It is important to have unique meta descriptions for each page in the website. The text used should again reflect the content of the page and match up with the body text of that page.
Keywords should be kept in mind when creating meta descriptions as these should be included to rank higher for key search terms.
Other meta tags include
Meta Keywords
Meta Robots
Meta Author