Welcome to the wild world of advertising.
I went to Iowa State University for graphic design. After I graduated I moved to Milwaukee, where I've been working as an art director for the last 20 or so years.
I also teach graphic design at the college level. One of the classes I teach deals with preparing your portfolio and interviewing as an entry-level designer. So, even though I may be at a different point in my career than you, I've got a pretty good idea what you are about to face.
Let's look at who your target audience is. First of all, target an employer with a job opening. Cold calling won't be very productive. Concentrate on the firms actually looking to hire someone. The exception to this would be if you have your sight set on a particular place you really want to work.
There are a few attributes that employers are looking for at the entry level. You won't have a large body of work or a work history coming right out of school, they know that. They are looking for is someone that is a decent designer, knows the software and really really wants to work hard. Keep these factors in mind when crafting your message to them.
Now for your resume: It should be nicely designed, organized and easy to read. Always be sure it’s accurate. If it’s not it can come back to haunt you later on. Make your objective reflect the benefits hiring you will bring: "To work with a team of exceptional creatives. In a fast-paced challenging environment where I can use my design skills to grow with the productivity and reputation of the company."
With this statement you are stroking their egos ("exceptional creatives"), saying that you work and play well with others ("work with a team") and that you thrive under pressure and that as your skills grow, so will the company.