Do you write your own copy?  If you read that sentence and said, “Huh?” then it’s good to know that “copy” is just the industry word for writing your own marketing.  If you do it all, you’re writing your own copy and this is can be a very specialized craft.  There are plenty of resources out there but one of the best I’ve run across is the website Copyblogger.  With great copy, you want to read everything on the site because it’s all relevant to learning proper copywriting and these people know how to do it.  The coolest part of the site is the blog and right now they’re running a series on the most important elements of copywriting.  Make this website a regular read and you’ll find your copy improves over time.