You can make this really easy on yourself. Once you get those meta descriptions and keywords in there, don't forget to add all those keywords into your descriptions on your home page, otherwise you can look at this tool and see your percentages drop and have no clue that you have to add these to your home page on your website too.
I spent countless hours with that tool which I do love, because there are a lot of other programs available on that site as well, but after I changed my meta tags my percentages would go way down, until I learned that I need to use those keywords in the descriptions on my home page. So if you change them or are using this tool for the first time do remember to use the keywords on your text content on the homepage too.
Here is the tool
http://www.seocentro.com/tools/search-engines/metatag-analyzer.html
