Many a helpful guest has screwed up a perfectly fine docking by just helping.
I have given up telling my guests to fend off if we're about to hit something. I now tell them to fend off only if I tell them to. Many times I've seen people reach way out of the boat with a boat hook to push off a piling that's a good three or four feet from the rub rail.
To the OP, one thing that helps me is to review and visulaize in my mind, when I'm about to make the turn in reverse down the fairway, how the boat is going to respond when I move the throttle and tiller. For example, I have a prop walk to port in reverse, and to starboard when in forward (the latter being very pronounced when I goose the throttle to stop my backward movement once in the slip.) Not only can I use the prop walk to help maneuver, it also helps me anticipate which piling I'm going to tend to hit and which piling I want to get that first line over (probably on opposite sides of the boat.) Coming into my own slip, I know exactly where to position my 10-year-old son with a boat hook, and I can tell him in advance what to grab. Meanwhile, I have a line set up through my jib track and I know which way it's going to tend when the line goes taught. Knowing how the boat is going to respond to throttle and tiller is going to help me predict these same things coming into a transient slip.
When I say visualize, I mean exactly that. It's easy to say, "it walks to port in reverse," but it's much more useful to look over the transom as you back in, and say, "when I hit forward throttle, my bow is going to swing toward that Morgan and the stern is going to want to hit the Ericson." And of course, the wind is going to have a say here too.
Finally, while there is an art to docking, there is also an art to not being bashful about the occasional less-than-graceful landing. It's highly unlikely you're going to come in too hot, plowing through your neighbors (I say this because of the details you provided,) so just go with it. As someone said in another thread, "they call them rub rails for a reason."