When you are writing an employment cover letter, there are three types of letters to consider, or three reasons why you might be writing an employment cover letter. These include:
One requirement that holds true for all types of cover letters is that you absolutely must write a specific, targeted cover letter to go with each resume you submit. Ensure that your cover letter addresses the specific employer's needs, and avoid submitting form letters that are basically the same letter (with the employer's name changed) sent to many different companies.
"There's no traffic jam on the extra mile." author unknown
It's very obvious to an employer if you have submitted a form letter, and it does not make a good impression. If you submit a generic form letter style of cover letter, the employer will typically feel that you have not shown any specific interest in the company and have not made any specific effort to apply for a position within his or her company. They will interpret that as a negative reflection on your motivation to work for that particular company and your work ethic.
On the other hand, if you write a specific, targeted cover letter, focused on the ways in which you can meet and exceed the employer's needs and expectations (based on your research), you will make a strong, positive impression on the employer. This type of employment cover letter shows the employer that you are motivated to work for the company and you can be counted on to do that little bit of extra work that most people will not do to get the job done well.
Employment Cover Letter Tip:
Just because I've said that you must write a specific cover letter for each job, that does not mean you must start from nothing each time you want to write a cover letter and submit a resume. Staring at that blank page is not fun, and you really don't have to do that more than once.
It's perfectly fine, in fact really smart, to write a general cover letter, one that is a good fit for most of the jobs you'd typically apply to. However, do not submit that general cover letter. Instead, use that general employment cover letter as a solid starting point that you can adjust and edit to fit with the specific requirements of each job that you pursue.