Sure, I will give you brief information on how to create your meta-description tag.
Firstly, every page on your website you will be managing must have unique content, thus, unique title and description. Since you should by now have your keywords and key-phrases you would like to target, what you do is make sure your title contains the keywords (title can be 64 characters long, though the best bet would be to keep it 64 characters, 64 characters will show when Google returns search results (that's why it is best kept at this), can use ms word to count characters to make your life easy)
You see, this keyword/phrase you are targeting in your page, is now in your title, therefore, your description can now start with it.
<title>SEO Services @RankYa Delivers MORE than just High Google Ranking</title>
<meta name="description" content="Seo services @RankYa delivers more than high Google ranking, like FREE consultation, FREE professional Facebook page design & FREE twitter page design" />
It is best to start the meta description with the keywords you are targeting, in this example above, it is seo services.
Take bit of time when writing these tags, while remembering, that the content within the actual page must complement what you are doing withing these tags.
We have while back made this particular video just for the question you posted here, I encourage you to watch it.
How to create proper meta tags = http://www.youtube.com/user/rankyaseoservices