Think of it as a kind of handshake; it introduces you to a recruiter and provides a snapshot of your experience, motivation, enthusiasm and fit for the role.
Don't ever be tempted to recycle the same old template!
Cutting and pasting may sound like a great time saving hack but you'd be amazed how many people lose the opportunity to be shortlisted for their dream job by sending a cover letter with the wrong company name on it! If possible, address it to a named person. Start off strong with a hook, something that really grabs the reader's attention. It doesn't need to be more than a page long but does need to cover the following key things.
Why them as opposed to any other company?
What makes them standout to you? Show you get who they are, what they do and why they do it. Explain how this resonates with what is important to you, reference their mission, their purpose, their culture, and your values. Mention how you've engaged with their company before, at careers fairs, on LinkedIn, insight days, campus events and industry related events.
Really highlight your understanding of what the role involves and why you are a great match in terms of personality and your career goals and aspirations. Are you interested in the role because you want to progress your career, change your career or because the sector interests you? How would this role stretch you? What can you uniquely bring to it?
Why your skills and experience mean you would be a success in this role.
Don't repeat everything in your CV, pick a few real highlights to talk briefly about and give examples. You can also address any gaps in your CV, any skills you don't have at the moment but are upskilling in, and any mitigating circumstances you want them to be aware of.
End with a call to action!
Show enthusiasm for the next steps in the recruitment process and wrap it all up with a thank you.
End the letter with Yours sincerely if you addressed it to a named person. If you don't have a named person, end the letter with Yours faithfully.
A great cover letter can really complement your CV and application, communicating your value to an employer and getting you that interview! See suggested resources for more advice.