I think you should continue to glue yourself to the chessboard and use your time well as you have been doing in the last 15 games. When you have lots of time and they do not==they will tend to make mistakes or blunders.
This is very hard but if you want results...
Contratulations on very great results over your last 15 games!
Getting up from time to time is a good idea. I think you should look for a happy medium between your two methods.
Thanks for the input. Any advice on how to improve mental/concentration endurance?
Oh, and since you love the ponziani so much, let me show you my game against the 2200.
His last 20 or so moves were played in intense time pressure and he was under 3 minutes for most of it
I'd mix it up. You don't need to stay seated all game. You should get up in positions where you are comfortable with the position or have a good idea what your next move is going to be. In fast games (G/60) probably staying seated is a good idea or limiting yourself to getting up only once or twice. Even standing and looking at the board can help get the blood flowing better and help you feel more alert. In more normal time controls though (40/2hr+1hr or even G/90) getting up from the board in my opinion is a must. You just can't sit at the board for hours on end and concentrate to your best ability and even if you did you'll get exhausted doing so game after game in a tournament. Remember no one wins a medal for having a bunch of time on their clock after games so as long as you avoid time scrambles then it won't hurt you to get up and walk around, look at some GM games in progress and lose some time off your clock from doing so. Even in critical positions this can help you sometimes with fresh eyes, increased blood flow and all that.
What about coffee/energy drinks? Would those help or hurt my concentration/thinking process during games? I also have a hard time sleeping before big tournaments. It's a problem lol
I like to sit at the board the whole time, but I can definitely relate to fatigue in the longer time formats. Actually if they're taking a very long time, and I find myself analyzing the same stuff again and again, then I'll get up.
I have to stay away from caffeine unless it's the last round of the day because a few hours later I'll crash. Might sound coney but I recommend fruit juice and peanuts for an energy boost. Also helps so you're not as hungry at lunch as a big meal can cause sleepiness too (for me anyway).
I'd stay away from any energy drinks/caffine. You'll get a crash at some point and feel awful. Drinking water helps boost your cognitive function and doesn't give you a crash. I'd also recommend Rooibos tea. You can google it for more information but it can help you sleep better and improves cognitive function among many other health benefits.
I will be at that same US Open tournament next week (6-day schedule).
I'm about 2100, and I can tell you what I do that seems to work really well for long time controls:
1) Do not get up after every move. As post #3 says, from time to time, yes, absolutely.
2) When you do get up, take a mental camera shot of the position. Even if you are going to look at your friend's game to see how it's going, you can easily count that he's up a piece and pawn, but mentally still in the back of your head is what's going on in your game. When I go to the men's room, I'm thinking about my position. The long term threats that my opponent has that I have to continue to keep an eye on, the long term ideas, etc. Save the short-term tactics that are prevented by a single move for when you are at the table. They aren't worth dwelling over!
3) I see this one all the time. If you literally have only one move that makes any sense at all, or only one legal move, just go ahead and make it. Why waste time? Keep in mind, I'm not talking about legitimate intermezzio moves. You might contemplate recapturing the Queen versus giving a Knight or Bishop check first, but you aren't just going to make a useless pawn move, and if you are say, in check, where the only sensible move is to capture the Queen, just go ahead and recapture it. If your opponent makes his next move quickly, then spend the time trying to figure out how to survive.
However, two things are certain. First, if you have only one legal move, and you have a complicated move coming up, if your opponent actually spends time on his move, you can calculate some of this stuff on his time rather than your own! Second, let's say you are in check and it looks like you are hurting. You have only 1 legal move, 46...Kh7, with 32 minutes left for the rest of the game. I see players spend 15 minutes on this move because they are either contemplating a difficult 47th move, or because they are debating between 46...Kh7 and 46...1-0 (Resigns). In the case of the latter, do you really think you are less of a man if you resign on move 47 instead of move 46? When there's only 1 legal move, I don't resign unless I instantly see that it's an immediate loss, like a Royal Fork, or an upcoming mate in 1. Never dwell when there's only 1 legal move!
4) As Wafflemaster has said, don't eat heavy, lead-like meals between rounds. If there is a really short time between two rounds in the same day, and the first one took me the full time, I'll grab a snack to hold me over and eat after. Having a stomach full of lead will make you play worse, trust me!
You can't argue with a 14,5/15 score...
But I'm unfamiliar with the tough scheduling of US tournaments 
I will be at that same US Open tournament next week (6-day schedule).
I'm about 2100, and I can tell you what I do that seems to work really well for long time controls:
1) Do not get up after every move. As post #3 says, from time to time, yes, absolutely.
2) When you do get up, take a mental camera shot of the position. Even if you are going to look at your friend's game to see how it's going, you can easily count that he's up a piece and pawn, but mentally still in the back of your head is what's going on in your game. When I go to the men's room, I'm thinking about my position. The long term threats that my opponent has that I have to continue to keep an eye on, the long term ideas, etc. Save the short-term tactics that are prevented by a single move for when you are at the table. They aren't worth dwelling over!
3) I see this one all the time. If you literally have only one move that makes any sense at all, or only one legal move, just go ahead and make it. Why waste time? Keep in mind, I'm not talking about legitimate intermezzio moves. You might contemplate recapturing the Queen versus giving a Knight or Bishop check first, but you aren't just going to make a useless pawn move, and if you are say, in check, where the only sensible move is to capture the Queen, just go ahead and recapture it. If your opponent makes his next move quickly, then spend the time trying to figure out how to survive.
However, two things are certain. First, if you have only one legal move, and you have a complicated move coming up, if your opponent actually spends time on his move, you can calculate some of this stuff on his time rather than your own! Second, let's say you are in check and it looks like you are hurting. You have only 1 legal move, 46...Kh7, with 32 minutes left for the rest of the game. I see players spend 15 minutes on this move because they are either contemplating a difficult 47th move, or because they are debating between 46...Kh7 and 46...1-0 (Resigns). In the case of the latter, do you really think you are less of a man if you resign on move 47 instead of move 46? When there's only 1 legal move, I don't resign unless I instantly see that it's an immediate loss, like a Royal Fork, or an upcoming mate in 1. Never dwell when there's only 1 legal move!
4) As Wafflemaster has said, don't eat heavy, lead-like meals between rounds. If there is a really short time between two rounds in the same day, and the first one took me the full time, I'll grab a snack to hold me over and eat after. Having a stomach full of lead will make you play worse, trust me!
thanks for all of the great advice! Your third point is actually very true. I've done that so many times.
Playing OTB well requires staying at your seat throughout the whole game. I have always done this, and it has worked out good.
Also, How would you guys improve mental endurance/stamina? Is there anyway someone could train it?
Sleep well before and during the tourney.I love to walk around during the game but i get up after every move which is a bad habit and Im trying to correct it.Have some Coke or any other drink you like with you at the table.Have some chocolate too if you feel like it. http://www.wikihow.com/Improve-Stamina
Rethinking my advice to stay at the chess board. Instead during the first part of the game I would be glued to the chess seat and try and play the very best moves and try to obtain also a time advantage. Only when you think you have enough advantage should you take a short break such as to get up from your chair and walk around a bit. But not too long as you do not want to lose the thread of the game.
When I played, I was always under great strain. So what I would do may or may not help others.
If you can get a good nights sleep before a tournament that would be great!
Update
The count is 21.5/23 drawing two more 2200s. Achieved the master title. Thanks guys
Way to go!
Congratulations! on a super performance and achieving the master title!
You had 3 draws and 1 win vs 4 masters?
In these 23 games, i played 6 masters. i had 4 wins and 2 draws. The other draw was vs a 1900 lol
Hello chess.com,
Those of you who have gone to OTB tournaments, especially in the States, know that tournaments can take a lot out of you. 8-12 hour days are not that uncommon in some Open events.
Previously in tournaments, after I had made my move, I'd get up from the board and walk around the tournament hall and pace around until my opponent had made his move. With this method, I was not constantly fatigued and felt pretty good during each of my games. However, my results with this method have been pretty bad. I would find myself consistently re-analyzing positions from scratch and wasted a lot of time.
In my recent tournaments, I have tried to correct this. From the start of the game, I would glue my butt to the seat and would think constantly. After I had made my move, I would continue to analyze/calculate variations on my opponent's time. I found that in a majority of positions, I could predict my opponent's candidate moves and make a move as soon as they did. With this method, I have gone 14.5 out of my last 15 games. Furthermore, I would almost never be in time pressure. For example, in most of the g/60 games I played, I was never below 20 minutes. However, I found that after each one of these games, I would be fatigued and sleepy.
How do you think many top players utilize their time during games? My 15 opponents were luckily mostly rated below me (only 2 games were played against 2200+). However, during the upcoming US open, future open tournaments, I would be facing much tougher opposition and my fatigue would most likely affect the results of these games. What do you think I should do?