- Present a clear thesis.
- Provide evidence to support your claims.
- Bring the story to a close with a succinct and compelling conclusion.
Not sure a cover letter is necessary? Think of the cover letter as part of the resume. If someone asks for a resume, send a resume plus a cover letter, unless there is an explicit request otherwise. This is standard practice. Also, if you are applying online and have a small text box in which to provide additional information, consider this an opportunity for a mini-cover letter.
Steps to Success
If you are new to cover letter writing, take this short course to get an overview of the most important aspects of a successful cover letter. In this course, you will learn about the purpose, value, and ways to prepare and develop a strong letter. 
Make a strong first impression in the first sentence of the first paragraph. A persuasive first sentence tells the reader that you are serious and keeps them reading. Interesting and compelling information about your candidacy should be introduced in your first paragraph. The final paragraph is too late.
Go beyond general statements that could be true for the majority of candidates. Common qualities or characteristics will not help you to uniquely stand out. Trust the resume to cover the basics and use the cover letter to highlight bigger patterns of success or share an anecdote about your achievements that relates to a requirement of the position.
Tell the reader about you. Communicate your interest and motivation to apply by connecting your background and interests to your knowledge of the organization. Avoid reporting facts. The reader already knows his or her organization but wants to know about you and why you are applying. This is a great opportunity to show your level of research on the position.
Use evidence to build credibility around every claim in your letter. The reader wants to believe you and needs detailed illustrations of your past success to do so. If you have included more than a couple of claims (two or three are sufficient) about your ability to thrive in the job, you are sacrificing depth for breadth and duplicating the work that the resume should do. Move extra information for the cover letter to the resume to improve it and trust the resume.

Cover Letter Template

Undergraduate Cover Letter Examples

Graduate Cover Letter Examples