Over the past few months I’ve written about working on my Pitata Magic Time Hacker routine. One thing I noticed in a picture of it was that the gray hands on the white background don’t really pop visually onstage.
I took a black marker and colored in the hands on one of my clocks:

It really makes the hands easier to see and the clock play a few rows further back in the audience. The bigger issue that I think this trick is fighting visibility wise is glare off of the plastic clock face. I don’t think there’s really a reasonable solution, unless there’s an easily applied anti-reflective coating, but even then I don’t know how much that would actually help.
-Louie