ADK, don't give up on your spotter. She and you can train each other to work together. It takes a lot of practice. Ron's suggestion about standard gestures is a good one. It is also important that she stand where she can see your mirrors (so that you can see her!).
When it is pitch-dark (like when we are preparing to boondock on a moonless night), we use walkie talkies. Headlamps are helpful, but I can't see her hands well enough.
After several years of trailering, she eventually got so good at guiding me that I wrote this tribute song, to the familiar tune of "Pinball Wizard:"
Ever since I was a camper
I've worked with my hitch ball
From Glacier to the Tetons
I've tried to hitch them all
But I ain't seen nothing like her
In any campground at all
That’s my own DW
Sure plays a mean Hitch Ball
She stands like a statue
Becomes part of the machine
She can see my bumper
Always hitches clean
She plays by intuition
That coupler neatly falls
That’s my own DW
Sure plays a mean hitch ball
She's a Hitch Ball Wizard
There's got to be a twist
A Hitch Ball wizard
She's got such a supple wrist
How do you think she does it?
(I don't know)
What makes her so good?
She never gets distracted
Can't hear the neighbors yell
Doesn't see the taillights flashing
Brings me in so well
Always gets it hooked up
Never missed the ball
That’s my own DW
Sure plays a mean hitch ball
I thought I was
The Hitch Ball Star
But I just handed
My Hitch Ball crown to her
Even on my little trailer
She can beat my best
She simply leads me in
And she just does the rest
She's got crazy waving fingers
Never seen her fall
That’s my own DW
Sure plays a mean hitch ball . . . .