Their is an art to writing page titles and descriptions. Here are some tips:
You can use the Google Keyword Research Tool to do some keyword research and figure out which exact phrases are the most relevant and have the most volume. You can then incorporate popular phrases and keywords into your titles and descriptions. Remember though your title and description should be descriptive of the content on your pages.
Do a google search for a specific page topic and checkout the resulting top ranking pages or sites. View their source code and take a look at their descriptions and titles.