The tone of the cover letter has a significant impact on its reader. Although the cover letter is a marketing tool, it is important not to come on too strong with the hard-sell approach. A well-crafted cover letter that highlights your most valuable skills and displays an understated confidence will often encourage the employer to pay more attention to your resume. On the other hand, a poorly written or sloppily presented letter can dissuade a potential employer from seriously considering you. Proofread, spell-check, and proofread again.
Few things make a worse impression than cover letter typos.
Set the letter aside for a day before doing the final read or pass it on to a friend, colleague, or advisor who will give you constructive feedback. Get the organization's contact information right. Call before sending your materials to verify the contact person's name and the organization's address. Always use a gender-neutral salutation if you do not have the contact person's name. Keep the letter brief.