Cover letter do's and don'ts

Mohammed asks: What are the most important 3 things that you need to cover in a cover letter? which ones you should absolutely avoid?

Answer:
If I were to break a cover letter down into 3 things, here's what I came up with:
1. name/contact methods
2. what you are looking for and why, briefly!
3. how you can help solve the hiring managers problem and the qualifications to show that, briefly!

Don't to cover:
1. why you left other job
2. personal life issues -relations,housing, income, health
3. religious, political, race, gender, sexual, financial, lifestyle beliefs

BUT, the biggest mistake people make on cover letters: Sending one as a formality! Think about it this way- you're writing a LETTER to a PERSON explaining to them why you're interested in a job, and why they should be interested in you. If you think about it this way, you're letter will automatically be more interesting. You also have to know what your letter will be used for. Most busy hiring managers won't even look at your letter until after they've at least skimmed your CV/Resume (they don't have time). If they look at your resume and are still interested in you, they might read your letter for more information, or to answer questions they have about you, like "Why does he want this job?" A basic cover letter style should address:

Paragraph 1: State why you're writing the letter. (position you're applying for, and an overview of the contents of the rest of your letter)

Paragraph 2: Describe why you're qualified. (Give an overview of the highlights from your resume, and explain how these have prepared you for the job you're applying for.)

Paragraph 3: Provide supplemental information. (Make it interesting. Examples of topics- why you want the job, why you chose this career, your philosophy relating to that profession, how you would go about doing a certain aspect of the job, etc.)

Paragraph 4: Sum it all up. (Conclude, express your interest in an interview, thank them for their time and consideration.)