Hi Tin_Basu,
I can provide some advice, but there is probably other useful information that more experienced players than myself can offer.
1. Do not let your emotions (fear, etc.) get the best of you. If you allow yourself to be carried away with emotion, then you might miss a move or idea that improves your position.
2. Look for the weakest points in your position, and keep the pieces that protect these weaknesses. If you allow more weaknesses to appear, your opponent might catch onto this. It is even harder to defend a difficult position when you have several weaknesses that are being targeted.
3. If your opponent begins an attack, don't blindly trade your pieces. The reason for this is that at some point you might have an opening in the position which will allow you to gain counterplay. Counterplay, I believe, is the ability to essentially turn things around, so that you can start taking control.
4. Try not to let your opponent's inactive pieces become active. If your opponent has a piece or two that aren't doing very much, don't play in such a way that allows these pieces to become active.
5. If you can't find any ways of changing the game around in your favour, try to eliminate the weaknesses in your position, and wait for your opponent to slip. But always be on the lookout for ways of taking control of the game.
I'm sure others can add more, but I hope this helps in some way.
A lot has been written on magazines and chess book about how to control position when you are a piece up or how to convert the material advantage to a beautiful win.
Well since i am a very very very weak player i dont need to know about it for now
BUT i want to know how to handle situation when i am a piece down or positionally worse. Well i don't know honestly positional play, i am a player who always end up blundering. So pliz pliz pliz i need your valuable suggestions as how to control my game when i am in a worse position.