When writing a meta description you should make it relevant to the page’s content. You should aim to highlight what the pages aim to get across. The description should link in well with the title tag the meta keywords and the pages main content.
The length should be about 150 which is displayed in google’s search results.
To begin with lets look at the Page Title. Firstly a page title should be relevant to the page and not the site.
Your page title should be descriptive, useful, relevant and if selling mention how the reader will benefit.Google uses a maximum of 68 characters for a page title yahoo is a little more 100.
Use a free tool like this to check your meta descriptions and their length revelance.
http://www.hypergurl.com/form.html
