First, read the English article below.

You should write your letter the same way you would if you were applying for a paid position. Be professional and consistent in your letter, as a poorly-written letter of interest could cost you the position.  Use a uniform type size and font that are appropriate for a business letter. Stick with a font size between 10 and 12 points, and choose a font that is easy to read and has clean lines, like  those in the sans serif family. Some examples of professional-looking fonts include Arial, Century Gothic, Futura, Lucida Sans, News Gothic, Technical, Times New Roman, and Rockwell.  Do not use any unusual or unique colors in your letter. Type the body of your letter in black. You'll want to follow proper formatting protocol to make your letter look as professional as possible.  Write your contact information in the upper lefthand corner of the document. Include your full name, address, telephone number, and email address.  Insert two or three line breaks, then write out the contact person's information. Start with his or her full name (or a proper title, if no first name is given - for example, Ms. Stone), the department that person works in, the name of the organization you are hoping to work with, and the organization's address.  You may wish to include the date on your letter so that the person reviewing your application can see when you applied. This can be inserted between your contact information and the organization's. The first thing you should do (after including your contact information and the organization's contact information) is to address the letter's recipient with a proper title. If the recipient is a doctor or has earned a doctorate, address him or her as Doctor. If not, use Mr. or Ms. If the gender of the recipient is unclear, use the person's full name rather than a title. If there is no contact person listed in the announcement and you cannot find out whom you should address your letter to, you may be able to get away with using a subject line instead of a formal salutation. This part of the... 

Now, please write a short abstract for it in Vietnamese. Abstract:
Viết một cách chuyên nghiệp. Định dạng bố cục lá thư. Mở đầu thư. Viết đoạn đầu tiên. Viết đoạn thứ hai. Viết đoạn thứ ba. Kết thư một cách chuyên nghiệp. Ký tên.