yep.. im scared and stressed during a chess game, so is my opponet. but how do i keep calm under time pressure.

take out your karate black belt, heavyweight champion belt, and a crown, put them on and show your opponent who's boss.

nice one :) but im serious...

If you are serious, then be more detailed. 

Are you talking about OTB, are you talking about online. What time control is this as well, blitz, rapid, bullet, standard. 

Depending on how you answer the above, will change my proper answer.

well not online. when i play against someone stronger by title or rating in real life im really stressed out. if im playing someone close my rating range or lower than me im not... i usually play 10 minute blitz.

Focus on the position and calm down your breathing. If you can't look at the pieces and start visualizing what they can do, you can't play chess competitively.

Stop thinking about things around you, and start thinking about the game. Sounds easy, really is not.

I used to deal with the same issue playing varsity sports. I think experience helps the most. You get used to playing in events and eventually you just stop getting nervous. Being prepared as best as possible also helps. Youll be more confident and less nervous because you put the work in to be ready.

jiggur a moonshine       doeser ever time

Be like Steve Seagal. Or Bruce Lee. Defo not Mr. Bean.

"Pressure is a Messerschmitt up your arse, cricket is not" (Keith Miller, Australian cricket legend).

so you're saying perspective matters? mmm thank you!

But of course Tuna! Just ask that fish of yours.

Focus on breathing or other physical sensations is good (feel the weight of your feet on the floor / your back on the chair), or develop a mantra you can repeat to yourself silently.

Most of all, take a second to smile and remember you are playing a game, and should enjoy yourself!

I personally like to pace around the room and focus on something other than the game when its not my move e.g. another gme or some decorations in the room

a new chess.com video called 'Don't Lose Your Cool' was posted today.

by GM Melikset Khachiyan

http://www.chess.com/video/player/dont-lose-your-cool

If losing your calm is related to time pressure then (I think) the best thing to do would be to play with shorter time controls. Either you will get used to having less time or not... but when you return to your normal 10 minute games the time control will (hopefully) seem more generous. :)

I've noticed that my ego sometimes gets all cramped up, especially when playing blitz. The ego is so afraid of loosing. That's a mistake. We should do the calculations fast and focused, without involving pride. I believe a pro juggler is totally calm inside.