This is a great article from Glass Door about how to be better at sending emails, especially when it comes to cold emailing about a possible job opportunity.One additional thing I would recommend to everyone, and especially those who have English as a second language, is to try out Grammarly.

Grammarly works in the browser for web based emails, as well as in Outlook and across MS Office products. It keeps track of your writing and offers recommendations when you misspell words, and it lets you know if you've missed/misplaced a comma or apostrophe. Each month it gives you an overview of where you're making mistakes so you can work on improving areas of your writing.

Geez, sounds like I'm selling it, right? I'm not, but it has been super helpful for me and I can't recommend using it enough.