Like it or not, your cover letter is the first document that creates an impression about you (good or bad). Because first impressions really count, you need to take a careful approach to writing cover letters in order to avoid rejection. Here are the 10 major don’ts you need to avoid:
1. Don’t use cover letter templates, however good they may be. There are three things you must know that go against these templates: 1) they are stale & boring 2) most templates are likely to have been downloaded from internet 3) therefore, yours will be exposed as being identical to many. Use samples to get ideas on how to write your own unique letter.
2. Don’t write a lengthy first paragraph that will only bore the reader. A lengthy first paragraph also dilutes your impressive qualities and eventually weakens the entire letter - this is the last thing you want to happen.
3. Don’t exclude your Unique Selling Proposition, or USP. Remember that the cover letter is your sales letter; you should highlight your main strengths and prepare the reader psychologically to want to read further.
4. Don’t write a vague letter without mentioning specifics, such as the job title and job code/number if you are responding to an advertisement.
5. Don’t address your cover letter ‘To Whom It May Concern’. It shows that you don’t care enough to do your research to find out who is receiving the resume packages.
6. Don’t use fanciful fonts. Don’t unnecessarily use capitalized or bolded words, or grandiose phrases. Don’t send the letter without nixing silly spelling or grammatical mistakes.
7. Don’t use cliché language such as "As afore mentioned, I am enclosing…" This will only irritate the recruiter. Instead use simple phrases such as, "enclosed please find my resume."
8. Don’t include personal information like your race, sex or marital status in the cover letter. These things are against the Equal Employment Opportunity Act, and as such will not impact the decision whether or not you are called for the interview.
9. Don’t use copies of the same cover letters with just the address and date lines changed to send for similar jobs. If you don’t customize the entire body, the letter may either be irrelevant or a mistake may silently make it into the final draft.
10. Don’t brag or make statements that can't be quantified. You should be humble, yet accurate – employers these days often verify your statements for accuracy (and uncover exaggerations).

The trick with the cover letter is to capture the reader’s imagination as soon as they begin reading. This entails keeping your cover letter neat and tidy with a simple format, and avoiding common errors, such as the 10 listed above.