Turning points are the major plot events that cause some big change and modify the trajectory of the characters in the plot. But the "turning" comes from the CHANGE. It's not just a big dramatic event, it's an event that "turns" from what's come before. Yet, if you want a logical, coherent plot, you want that big turning event also growing out of what came before.
But think of the turning point as the culmination of something. Then set up for that in earlier scenes. Then the turning point will have something to turn FROM. It will be a pivot point from one situation to another.
This is especially important with the events that have a strong emotional component. You want to set up the emotion that will be changed or forced into conflict by the turning point. For example, the reversal is a big scene that happens usually in the middle of the story, reversing something that is "true" in the first half of the plot. Like: "I can trust Paul. He's my best friend." or "My boss is all wrong about this acquisition. He used to be really wily, but he's losing it." The reversal reverses this-- Paul turns out NOT to be a best friend, and the boss was right about this acquisition.
This is a great opportunity for a emotional buildup or set up. Set up the "before" emotion in the scenes before the reversal, and then try using a bit of opposite terminology (don't be too obvious, of course!) in the end of the reversal scene.
Let's take Paul. Keep it subtle, but in the scenes before the reversal, have the protagonist realize that Paul is his best friend. He might even say at some point, "Okay, Paul, whatever you say. I trust you." Doesn't take much to set up the association of Paul being the one the protagonist trusts. Then the reversal, when Pro discovers that Paul is the one behind the poison pen letters or whatever, will be emotionally as well as plotfully dramatic.
And the boss-- well, let's say the protagonist has been observing him. She sees some evidence of mental failure, like he looks at the financial material about the company to be acquired, and blinks, and thrust the page away like he can't absorb it all, and she thinks maybe even sympathetically that his once-sharp business mind isn't as sharp anymore. And of course his arguments against the acquisition might come across as prejudiced and unfounded: "I don't trust that CEO. He has a weak handshake!" And she can think that his prediction of failure in the acquisition are just a sign of his desperate fear of losing control of his company.
Then the reversal-- the utter disaster of the acquisition, on the Time-Warner-AOL merger level, proving that he was right all along-- can be that much more dramatic because it has been set up for AS A REVERSAL.
I really think this is a key to creating a dramatic and yet coherent plot. We can have all the right turning points, but they won't zing unless they really -turn-, and that requires setting up beforehand what they're turning from.
Examples? Who has a turning point event they want to share?