Send one! Even when an employer does not directly ask for one, you can still send a cover letter. But do not send a cover letter if the job listing explicitly says not to send one. Be sure to follow all directions on the job listing.
Customize each letter. It might seem tedious, but it is important to customize each letter to fit the specific job you are applying for. This will make your letter stand out.
Highlight relevant qualifications. In your cover letter, address one or two skills or qualifications you have that match the job description. Provide specific examples of times you demonstrated these qualifications.
Explain anything. You can use your cover letter to go into detail about something in your resume that needs explaining. For example, a cover letter is a great place to talk about a career shift or to explain an extended gap in employment.
Read samples and templates. For help writing your cover letter, read samples as well as cover letter templates. Remember to tailor any example or template to fit your own experiences and the job for which you are applying.
Edit, edit, edit. Be sure to thoroughly proofread each cover letter before sending it, looking for grammar and spelling errors. Consider asking a friend or family member, or even a career counselor, to read over your cover letter.