But there are NO Magical Expressions that you can simply drop in your email that can make you look sophisticated.

And that's not the point of an email anyway.

Stop for a second, and ask yourself, "Why am I writing this email?" Seriously, why do we write emails?
It's because we need something from our reader; we want our reader to understand something, hire us, take an action, etc. And a successful email is actually one that accomplishes such goals! A successful email is not one that contains "sophisticated" expressions!

That's it. We want the reader to do the action we hope for. No one cares about long complicated paragraphs or fancy terms. Quite the opposite. Most people are busy and are bombarded with tons of emails everyday. They have no time for this. All they want and appreciate is that they can get your message as clearly and quickly as possible.

A successful email is brief, clear, respectful and uses appropriate tone and fulfills its purpose (persuasion, request, promotion, etc.)

Do this instead

Be nice and polite. 

It's very simple to do that. Just be nice and polite.

For example, most people like to be appreciated. If you can say something positive about them or their work, do so. Sincere compliments won't be wasted.
People also like to be thanked. If the recipient has helped you in any way, remember to say thank you. You should do this even when it's their job to help them.
And people like to be replied to. So whenever you receive an email and are too busy to give a well thought-out response, just reply that you've received the email and you'l respond soon!