Increase line weight
Not all of them, just the smallest size. See how it's breaking up on some of them in the lower-right corner, especially.
Add tickmark holes?
Next to each measurement item, like form spacing dashed lines, and maybe the line spacing items. Just a hole small enough for a pencil, or even just a tiny mechanical pencil.
Rotate all Labels?
As described several places, the right way to use it with a portrait-orientation handset is to hold the template sideways. Then you can handle the part hanging off the edge of the phone, and won't interfere with the screen.
I wonder if I reinforced the wrong way with the orientation of my labels? What if the finger graphic and the labels were all rotated 90°? That might remind everyone to use it that way better. Or, maybe not.