Mention experience in the first paragraph
First things first. Mention your experience and willingness for the job in the first paragraph. Remember, your experience and willingness to work for that company is the most important thing. So, avoid writing things like how you want to be part of the company because you think you are the right candidate for the position. Also select key tasks in each of your past posts.
Do not repeat information in CV
Ensure that you do not repeat the information in the CV or application form — if you cannot think of anything different to say, at least make sure that you use different words to convey the same message.
Choose right words
Do not make your letter difficult to read, as it first goes into HR department before being handed over to those responsible for department of your choice. People responsible for recruitment may not be as technical as you expect them to be and using jargons may turn them off. Use a simple structure.
Be seen as a nice person
If you are putting in details of interests which are not self-centered, this will help the employer to envision you as a nice person. There may be hundreds of applications and many people capable to do the job, but the recruiter will see it as a bonus if he or she develops a liking for your after reading the letter.
Never say how bad your past employer was
Another way to come across as a nice person is to avoid mentioning negative points of your old employer. This will reflect your personality and the prospective employer may feel a bit skeptical after reading your application.
Aim to sound positive in your application. Be confident in your statements. Do not say things “I feel I am good at this.” Say “I am good at this.”