Dear Jithin,
There videos on Youtube that give "tips" on email communication. Nevertheless, most of the videos will teach you basics. As you are well aware with just "tips", you cannot become "expert" in any field. Therefore, what you need is taking 1-2 day training course conducted by some senior training professional. Recently, I conducted such workshops at Hyderabad, Bangalore etc.
In the meanwhile, without anyone's guidance, you can improve your grammar on your own. Lot of books are available on English grammar, how to write essay and comprehension. If you master these, more than half of the battle is over.
By the way, unless you read quality text, you cannot improve your writing skills. Therefore, read the editorials of the newspapers, especially of Times of India or Indian Express. Keep the dictionary besides you while reading and check meaning of
each difficult as you come across with.
I have been giving replies on the subject whenever queries on this subject came on this forum. Some of the replies are more than 6-7 years old but relevant today also. You may go through the following links:
https://www.citehr.com/218947-traini...tml#post986425
https://www.citehr.com/432407-busine...ml#post1987681
https://www.citehr.com/365556-examin...ng-skills.html
(please go through the entire thread)
All the best!
Dinesh Divekar