I understand what you are saying.
When your opponent plays a "non-book" move, it is your job to work out its deficiencies and then exploit them. Your ability to react appropriately depends upon your understanding of the position and playing strength.
There are no shortcuts, so join the club and suffer along with the rest of us.
Hi all I have a question which might seem a bit silly, but please bear with me! Ok, so I get openings, but I have one question. When I'm following an opening in a tutorial book, say my Chess for Idiots, or whatever, it explains the moves which I totally get, BUT it explains them as though your opponent is making the correct moves of the opening in reply. That hardly EVER happens to me. Within one or two moves the opponent makes moves that aren't part of the opening. I don't understand what you do then. It's a fundamental thing I just don't get. I'm sure top players play opening moves by the book, but when I'm paying someone on chess.com or a friend, they never play the opposing opening moves. Do you see what I'm not getting? I hope I'm being clear cause it's a question that's foxed me for so long. Is the idea that when they play non-opening moves you stick to the opening with the opening plan, giving you an advantage? That's just a wild guess, I really don't know. Please help! Thanks in advance. If you want me to make it clearer what I mean, please do say! David