Sharpen your vocabulary- how do you do it?

I read a lot and use new words that I encounter in my written communications & conversations.

You don't seem to have that problem. Your English is very good. I've never been a fan of grammar. If a sentence makes sense then it is a good sentence. No need to put that verb tense, subject verb crap. If it sounds good then it is good :)

One way of improving your vocabulary is to carry a small notebook with you in which you jot down any new words or idioms you encounter whilst reading or browsing the Internet. Either make a note of the meaning immediately or go back some time later, when it's convenient, and look up their meanings and write them down. One of the best aids to memory is the physical act of writing. Once you have several words, try to use them in your own writing (if they are appropriate, of course!) and make a mark against them in your notebook to show that you have done so. After a while, you will have a growing list of more or less useful words with marks against them them showing how useful they have been to you personally. Your friend may have remembered some of the words she crammed up on but she might have remembered many, many more if she had written them down and made an effort to actually use them!

She must be a walking dictionary. lol

First, read anything that comes to you. When you come across a new work look up for the meaning. After the read is completed recapitulate everything and write comments. This time, try to use the words which you had to look up in the dictionary for. ,

The easiest way to improve your vocabulary/learn new words is by picturing the meaning with yourself..e.g:oppression:imagine being oppressed by your teacher.. Another way to understand /learn is to get the equivalent meaning of the word in your native language...as a concern for your grammar development, i would say that the best way to develop literary skills is by writing as opposed to reading.. Many people would argue that reading will help you with your grammar. I agree with them.but,if you write your own passages, i am sure your grammar and literary skills would gradually improve in a short span of time with regular practice.

I try to pick up new words while reading. I have installed an app dictionary on my mobile, I usually check the meaning of the word immediately and try to use the word in conversations to remember it.