XI Obert Vila de Gracia, 6th Game: Speciously Sleepy Symmetry (Queen's Gambit Declined)
In the seventh round of the XI Obert Vila de Gracia my opponent didn't show. In the eighth round I drew Black against Armando Daguro Dasalla, Catalan ELO: 2093, Fide 1911 (Peak Fide: 2077 in 2009).
After starting with d4-c4 which I met with d5-e6, he played some slightly dubious opening moves and I by the time the dust settled I had forced an exchange of Queens and was a bit ahead in development in a completely symmetrical structure. The problem was, I had never played a position like this and so had to come up with a plan. I did fine, until I was surprised by a move, missed a simple threat, went ahead with my own plan, and lost on the spot...
The main lesson is that I really need to learn how to maintain the concentration and BLUNDERCHECK every damn move so that things like this don't keep happening to me... any and all suggestions of how you've been able to solve this problem for yourself are more than welcome!