META tags are a fundemental component of HTML and good SEO practices.  A META Description tag is a free advertisement in search engine results, so don’t waste it!

Your description “tag” appears near the title in the header area and should be unique to each page. It’s purpose  is to be an accurate description of page contents and goals,  of course including as many major keywords as possible. 10-20 words are appropriate since total length should be under 170 characters. This will appear in the results of some Search Engines, so it should not be just a collection of random words and phrases. Here is what the tag looks like:
<meta name=”description” content=”Brief description of the contents of your page.”>

META Keywords tag
While not nearly as important as Title and Description, the keywords tag should include any search terms that actually appear within the text of the page. The following practices are advisable: (1) keep your list below 20 unique words or phrases; (2) separate the words or phrases using a comma; (3) put most important word or phrases at the beginning of your list; (4) do not repeat words or phrases.  The keywords tag is not as important as it used to be in the early days of the internet.  But it’s use has been downgraded since it became an early source of “keyword stuffing”.

Invite search engines to map your site
Be nice to those search engine spider robots which are constantly crawling the web looking for new and updated files. Invite them to chow down at your picnic! The META tag to include within the header code of each page you want them to find/index would be:
<meta name=”robots” content=”index,follow”/>

Upload a robots.txt file
Another welcome to search engine spiders to visit your entire site is by placing a robots.txt file on your server to tell them which pages or sections to crawl or index and which to ignore. For example, you may not want an images directory or javascript file spidered. You may also issue individual indexing instructions to specific search engines. The file itself is a simple little text file, which needs to be saved to the root directory of your site (where your home page or index page is). In other words, you would
upload your version of this to your web host along with your HTML pages, images and other files:

#The following allows all robots to visit all files because wildcard is used
#But all robots are barred from cgi-bin images and scripts directories
User-agent: *
Disallow: /cgi-bin/
Disallow: /scripts/
Disallow: /images/

Again, be nice to the search engine robots and you will be richly rewarded!