1. The body of the email should itself contain the cover letter. Don’t attach a 300 word cover letter because it won’t be opened in ten cases out of nine. Ten out of nine? It might seem an exaggeration or a misprint but it is none.
Instead of sending your cover letter as an attachment, write it in the body of the email itself.
2. Subject of the email which is the subject of your cover letter should be detailed and educated, a bit like this: Internship Application: 1st May- 30th June: Mumbai Office.
These are the three things (subject + duration + location) should make the subject of your internship cover letter; nothing more and nothing less.
3. Focus and customise. Don’t send an email to dozens of law firms at one go. Identify 5-6 law firms which interest you and send applications tailor-made for them.
For example if you are applying to an IP boutique law firm, include a section in your CV (right at the top, mind you) which reads ‘Achievements in the field of IP’. Also in your cover letter mention these achievements precisely.
4. Art of the start. Start with naming the person you want this to read; the recruitment head, the managing partner or the internship coordinator. Do your research.
Assuming the name of the person is Ram Kumar and the email id for internships is firstname.lastname@example.org and you start with “Respected Mr. Ram Kumar” you catch his attention.
If you begin with Respected Sir/Madam you don’t get anyone’s attention.
5. Write English. Please don’t show of your legal writing skills here. Write simple, plain, correct, readable English. Reserve legalese for later, when you actually get the internship.
Do a spelling and grammar check on Word on your cover letter.