Generally speaking, a cover letter of about 1000 words is appropriate. The cover letter should be focused and targeted, and the length should not be too short or too long. On the other hand, the writing of the cover letter should adhere to the principle of seeking truth from facts, with sincere attitude, proper self-introduction and fluent writing. We can start from the following aspects: first, we should get to the point at the beginning and state our willingness to apply for a job; Second, sell yourself and briefly describe your major and related talents; Third, indicate the best way to contact yourself; Finally, thank the recruiter for reading and considering his application request.