When brainstorming for your cover letter there are two general effective ways to convince your potential employer. First you describe how you would be a good match with what they are looking for. Mainly you want to focus on what you can do for them if they hire you and how great of a benefit you could be to their company. Then secondly you want explain how you really want the job. Don't forget that when you do explain why you are interested in the position that it still needs to remain professional.
There really isn't a set criteria for how to write a cover letter but there is a standard formula that is easy for everyone to use. In the first paragraph of the letter you should state why you are writing this letter. Then follow that paragraph with a detailed description of why you are qualified for the job. The third paragraph is where you can provide supplemental information and then finally sum the letter up in your last paragraph.
Cover letters are always attached to the front of a resume when turning in an application. They must be neat and professional looking. The usual length for the letter is no more than one page with a size ten of twelve standard font and remember to always carefully proofread! Errors will make you look careless to your potential employer. If you need any help brainstorming or writing your cover letter call the Boise State Career Center and make an appointment; they are always willing to help!