REF THE DEFENSE. On the play where the defender is running alongside and parallel, it's very difficult for the the defender to get in front of the dribbler. Possible, but not likely. But when the defender is sliding to try to get in front and take the chard, oops! I mean charge!, they only have to be in the spot first, no matter how infinitesimal the instant is between the arrival of the defender and the arrival (crash!) of the dribbler. Watch the defender. That's how you know what came first. Forget travelling, and carrying. You'll miss a few of those, but getting the b/c correct consistently is more important. YOu'll eventually get the ball-handling stuff out of the corner of your eye. The most important part is

REF THE DEFENSE.

PS Also watch to see if the defender is moving backward, even slightly. If there's any contact at all, and the defender is moving backward, it HAS to be PC!

I agree with you. I think we are on the same side, but I did a poor job of making my main point. The point is that the call should be quick and decisive, unlike some where it is better to hesitate and try to play through slight contact. As you say, ref the defense, watch the defender, and if he's legal you will instantly know it, in your gut.
In this case my whistle goes off and my hand is on the back of my head sometimes before I even know what I called. As
someone posted: "Who initiated the contact?" The time I see that I most often disagree is when the 2 players are running parallel and the dribbler jumps into the defender trying to "draw a foul." Often this looks like PC to me and is called on the defender.