The problem you are facing is getting better at technique and this takes controlled practice where you get burned enough to stop making the same types of mistakes over and over again. Strong players do not throw clearly won games (especially against club-level opposition) as a rule.
Another issue you are facing is that as you move up the rating ladder,your opponents get stronger as well and won't bend over / play stupid once they are losing. Nobody's going to give you free trades of pieces (not pawns) because they know better. You have to use good technique to squeeze out the wins.
There are a lot of ways to use a material advantage to force situations that force a trade of pieces. After ensuring that he doesn't have any forcing moves to hurt me (do this before I play EACH move), you look for weak pieces/pawns and squares and apply force to tie his pieces down. Pin-based motifs are common to force a trade .Playing actively by using all of your pieces is another way to dominate the board. My favorite is to try to completely reduce the mobility of whatever pieces my opponent has left until he lashes out or starts pushing pawns and creating more weaknesses.
Above all else, keep the board as simple as possible. If you are winning, complications should be your worst enemy.
One way to train it:
1. Take any of your "losing when you are winning" games and lock down to a position where you feel you are winning outright (before you started to screw it up)
2. Plug them into strong program at max. level of strength.
3. Play for the winning side at blitz-time controls with a 5/second delay.
4. Once you feel you can do it, save this position and review it 2 weeks later. Can you still clean house? If so, then you've made steps to improve your winning technique.
Rinse and repeat this until you can win these positions in your sleep.
Also, post your entire losing games move-for-move here to get a stronger critique of where your technique is lacking. Your commentary description of the games only reveals what you think is relevant.
Hey guys I've been having a little problem here.
It's been converting extreme material advantages to a won game.
Yestarday night at the chess club they were having a Quick Chess Championship. Gm/20 with 5 second delay. They did 3 rounds yestarday, and they are doing the last 3 next tuesday night.
There were 2 games which I should of flat out won. But one of them I drew, and the other I lost!
Now get ready for the very shameful part. In the game I drew, I was up a knight for a pawn. So he ends up getting a passed pawn on the queenside, while we both have 2 kingside pawns locked. My king wasn't active, while his was because I never got a chance to get my king involved. I had to sacrifice my knight for his outside passed pawn. Then it was a draw. Doesn't sound too shameful?
The game where I lost was just unbelievable. I play the Scotch Gambit, which I think is a very good opening. There are only 4 mian replies. One of which you can prevent the king from castling at cost of a pawn. And remember all Scotch openings are very open so castling is a must in these kinds of openings. Two of which you can win a minor piece. One of which your opponent might be able to hold on, but White still has clear compensation. I'd say the game is about equal with this response. I play openings that fight for the initiative by the way.
So in this game I was able to win a minor piece, and because he was so thrown off, I even won an exchange (Rook for Knight/Bishop).
Why did I lose the game?
Well for one the time was only 20 minutes so there's clearly not enough time to be thinking about what your opponent has in mind. That's my weakness. I have trouble finding out what my opponent has in mind, and this is what you need to be good at when playing Quick Chess. My USCF Quick Chess rating is 1299(P10). I don't have a standard rating. But we'll talk about that later.
So I mislooked a simple tactic in which he was able to win a piece. So great he's got a piece back. Now I'm only up an exchange, and he was able to castle Queen side as a bonus. I gave him that option, for free. You know, as a gift. This person was rated 1768 Regular and 1495 Quick USCF. Then he traps my rook and now I lose the exchange. So now material is even and he has a Bishop for my knight. An advantage. And I had hanging pawns which he took. And then he won the game.
Now I know the key to winnning positions with material advantages is to trade down. However, my opponent kept declining trades. So how was I supposed to use that material advantage. What was I supposed to do with it. He was also attacking me on the King side, so I had to defend there as well.
Please if any player can tell me what should have I done, I will be MORE than happy.
Also, I've always estimated my USCF Regular rating to be around 1400-1500. Now I know this sounds ridiculous, but I've actually beat a 1550 player, and I've almost drawn against 1600-1800 players. Also, my Regular chess is a lot better than my Quick chess, because I actually have TIME! Although now after being so foolish yestarday, I'm really only hoping for 1300-1500. Our next long, serious OTB tournament is July 31, 2012. So I got time to prepare.
The other thing I think I'm doing wrong is that I'm not playing enough. I'm studying too much. Practicing tactics, learning middlegames. I also read as much as I was supposed to in Jeremy Silman's Endgame Course. I studied openings to much in my opinion. I'm stopping opening preparation for the time being. I've got a good repertoire. White: Scotch Gambit, Sicilian Najdorf Old Main Line, Blackmar Diemer Ryder Gambit (Note: I really hate playing Scandinavion, and it's still sound until you get up to at least NM level.) Black: Sicilian/French Defense, Benko Gambit. I have good opening preparation, and I don't need more. All I need to do I think is study tactics, play games, and do a little bit of middle game studies. I've already read through more than enough for endgames (in Jeremy Silman's opinion). Is my improvement plan good? Tactics, middlegames, and gameplay. I'm not going to get any better if I don't practice what I learn through studying.