Please guide me with some example. I am facing this a lot... Coz of this I am losing my time and also blundering the pieces....
You are playing a lot of Blitz 3+0, a time control which gives you virtually no time to think. My advice, if you want to improve your game, is to play longer games, preferably with time increment. You will then have time to work out how to deal with your opponent's pressure and you will blunder pieces less often.
