1. Title Tags
Title tags are critical because search engines not only use them when deciding what a web page is about, but they also appear in search results as the first line "Title" of your listing.
Think of title tags more as a "Title Keyword Tag" and include keywords that users would likely search for to find the content on that page. Keep them short and sweet. They are the first thing people searching for your site will see, and can never be more than Google's limit of 69 characters, including spaces. Your Title tag should look this in the HTML code of your page: <title>Title of Your Page</title>. It should be placed in the top <head> section of the page.
2. Meta Description Tags
Description tags will often be the text search engines choose to display in their search results page, and can have a big impact your search traffic.
It's simply a short description of the content or topic of a webpage placed in that page's HTML code. Your Meta Description tag should look this in the HTML code of your page: <meta name="Description" content="Your informative description here">. It should be placed in the top <head> section of the page.
Google's guidelines for writing good Meta Description tags:
The keywords used in your title and description tells your targeted audience this page is what they are looking for. Users searching for particular words will naturally first examine page titles, but if they still cannot determine which site best addresses their needs, they then turn to the most relevant page descriptions. By placing 1 to 3 keywords into both your title and description (which will appear in bold in the description tag if they match the search term), you're assuring search users that your site isn't in their results by mistake, but because it's what they are searching for. You should always write them, and the page they are on, with 1 to 3 very specific keywords or key phrases that are also used within the content of that page.
The title and description tags should always be specific to the page they are on and contain key words or phrases also found in the page heading, and the first one or two paragraphs of that page. Google compares words and phrases in your title tag and description tag with page content to be sure they are "relevant." It will ignore your tags if they are not. Write with flair, but be accurate. Your primary goal is to write something that will entice people to click on your listing in Google.