The best way?
Depends on the era of book, and type of CT applied.
SA can be totally different then GA due to inks, coverstock, and gloss.
Was it topically applied with s brush? Or colored in with maker? Or pencil?
Most of the time, if you hold a comic off angle, under a decent light source you will find CT stands out as you move the comic around.
As mentioned already, comics are printed in a manner that makes hand applied CT recreation impossible. All one can hope to do is mimic the intended color, and fool the eye. It looks muddy compared to original dot matrix.
As Roy said, once you get used to seeing CT, it stands out. Some worse then others.
All depends on the amount, and type of CT applied.
Bleed through obviously being very easy to detect.
As Roy said, CT is like porn. When you see it, you know it.
Or maybe he didn't say that exactly.