In my case, I've also just forgotten a lot of my script as I've switched from writing for others to read to my own notes. I never had good handwriting--as I recall it was consistently my worst grade in elementary school but I did know how to make the Palmer script letterforms even if I didn't execute them elegantly. Today I don't really even know them except vaguely.
Taking the time, slowing down and being aware of writing immediately resets my handwriting.
Also, the smoothness of the pens affect your handwriting legibility. A fast pen like a Uni Jetstream makes my writing worse. OTOH, a slightly resistant roller, a gel pen or ideally a fountain pen brings out the best in my handwriting.