Qbd?...Q.G.D?
Queen's Gambit Declined Help!
I'm assuming you're asking how to defend the Queen's Gambit by declining it rather than accepting it or playing something like the Nimzo-Indian. In that case, I'd suggest simply studying up on a straight-forward variation like the Cambridge Springs or, my own favorite, the classical Slav Defense.

The opening is not hard to play since the conflict is usually saved for the middle game. You need to understand how to play the middle game. Reading up on manority attacks, isolated queen pawn games, and hanging pawns would be a good place to start. In other words get a good book on pawn structures.

Read this book: Middlegame Strategy with the Carlsbad Pawn Structure, by Robert Leininger. BTW it is not correct to play the queen knight to c5 in front of your c-pawn, in the Orthdox Defense. The queen knight belongs on d7.

At least he would have some concrete ideas of what he should be playing for. That seems much more basic than trying to understand an opening like the QGD dealing with abstract principals and no notion of why the moves are being played. If he would just play through the moves (even without 100% understanding) he would have a greater understanding than what he will get from an opening book. You can't separate the opening from what follows.

Hey!
Just dropping in to say that the diagram above is not the only way to play the QGD. As a career Queen's Gambiteer I must say that my favorite games against the Orthodox go a little something like this:
Can somebody please explain to me how to play the QGD?
I have seen a lot of people play it and I can't really get a hang of it.
Help!!