1. Get off to the right start

If you have a full named contact, use it. If not, why not telephone the organisation and ask them for the main contact? If you can't find anyone specific, stick to 'Dear Hiring Manager'.

2. Make your opening pitch

Include the job title or position you’re seeking (if you’re writing a speculative application) and where you found the opportunity. Briefly outline your credentials, and motivations for applying for the role. Make it powerful, punchy and concise. You can expand in more detail in following paragraphs. 

3. Demonstrate that you understand the role

Explain how you meet (or exceed) the job criteria, and show that you possess relevant experience and skills based on past experience. Give concrete examples, which echo key words in the job description – the employer will be scanning for these. 

4. Bring your CV to life

Refer to your CV or other application documents to provide backup evidence. You don’t need to say it all, or duplicate your CV, in your covering letter. Your covering letter should animate key points of your experience that are relevant to the job description.

5. State why you're interested in this employer

If the organisation’s culture and development opportunities attract you, then say so. This is also your opportunity to demonstrate that you have researched their activities and possess true motivation for the role. Be specific, and link their mission to your own interests.

6. Close on a positive

Make your closing line constructive, not rambling. If you used a named contact, end with ‘Yours sincerely’, otherwise use ‘Yours faithfully’.

Harriet from the Careers team gave me a lot of advice on how to structure the content, add details about my experience, and even help me modify my tone to fit British job-hunting habits.