A cover letter is sent along with a CV in order to hopefully be accepted for an interview. The cover letter is the single most important document which will help or hinder your progress for an interview.
The cover letter needs to clearly explain why you are the right candidate for the job. You should clearly answer any questions included in their job description or advert. Try to refer to specific parts of your CV if you can too.
The cover letter should be typed on A4 sheets of paper, no longer than 2 pages in a sensible font. Size 12 Times New Roman is a good choice as although a little boring, it is easy to read and looks professional.
Make sure you tailor your letter to each company. You can use a template, however, make sure you include specific details about the job you are applying for – and really make sure all the names and addresses for the job are correct! Nothing more embarassing than putting the wrong name into the letter!