Cover Letter is not your autobiography or life history
This is the probably the most common mistake people make while crafting a cover letter. They think that mentioning their achievements in the letter will convince their prospective employer and they will get an interview call.
Avoid messing up the first sentence
The first sentence of your cover letter is important. If you write things like “I am writing to apply for this job,” chances are your letter will fail to make an impact. In order to come up with a surefire letter, start with strong words. If you are applying for the position of sales manager for instance, write a sentence like: I have ten years experience as a sales manager, with a proven track record of achieving targets within tough deadlines.
Keep it short
Long letters are usually frowned upon, and when it comes to applying for a job, time consuming application letters must be avoided. Officials with the task of hiring employees do not have time to dig deep into you cover letter, as they usually scan through the first few lines. And if your letter is concise and states the reason for applying in a few sentences, the employer will then move on to your CV as the second step.
Avoid distracting format and layout
The formatting and layout of your cover letter should be clear. Using fonts like Arial with size 12-point is good. Keep in mind your font size should not be too big or too small.
Avoid grammatical and structural errors
Use correct grammar and structure of the language. A complex language structure may distract the reader as he/she is not supposed to assess your writing skills.