From Pop Sugar
Once you've got your CV and cover letter ready, it's time to shoot off an email, cross your fingers, and hope you get an interview. There are things you can do to better your chances to get an interview. Try these the next time you apply for jobs. Reddit also has some more tips.Put all your docs into a PDF
There's nothing like having to attach 10+ docs to an email. It's not fun for you or the person getting the email. They have to download everything and it's easy to lose docs. Create one PDF and attach that to your email. Your cover letter, CV, and anything else they ask for should be in it. If you have a Mac it's pretty easy to do through Preview. If you have a PC you'll have to either buy software that allows you to create PDFs or try any one of the numerous websites out there that will do it for you. It looks much more professional to have a PDF doc and you don't have to worry about the other person not being able to open it or the formatting getting messed up.
Make a list of your documents you are attaching
I always, always list out exactly what docs are in the PDF that I attach. Having a list makes it easy for the person reading the email to make sure that you sent everything they asked for.
Limit the size of the attachments
Read the advert carefully. Many places won't accept files bigger than a certain size. Stay within that limit.
Follow directions
Again, read the advert carefully. Many times they will tell you to email one person if you have questions and email another if you want to apply. Don't email your app to the person you're supposed to email if you only have questions. Watch the deadline. Make sure to include all the docs. Be sure you fulfill the reqs, or almost fulfill them. Not following directions is a good way for your app to be deleted.
Put your info in the subject line
I always write my name, how many years of experience I have (either total or at that particular level, depending on the advert), my qualifications, and my visa status. It helps your email stand out and makes it easier to find if they need to.
Address the email to a specific person
Forget sir or madam or hiring committee. Find out who's hiring. Only use a generic greeting if the school you're applying to refuses to tell you who's in charge of hiring, which is always a possibility.
If you're not job searching you should still be networking. Check out how to write a networking email that gets results for more info.