Lateral CA, there's not much you can do about it--it's inherent in the lens, and you just correct for it in post-processing.
However, there's a second kind of CA which is most commonly referred to as purple fringing, but can also show up as red sensor bloom. This type of CA tends to show up on the edges of blown highlights. The explanation I remember is that it's a matter of a specific pixel "overloading", and the charge creeping from it to surrounding pixels. This is a combination of lens and sensor, and most commonly affects very fast lenses when used at large apertures (f/1.8-f/1.0).
The easiest ways to reduce this effect are to 1) make sure you don't blow any highlights (avoid shooting backlit things), and 2) to stop the lens down. In post-processing, you can desaturate purple to reduce purple fringing.
Stopping a lens down often improves its vignetting, CA (both lateral and fringing), and sharpness. Shooting wide open is nice for the bokeh, but it does have its cost with most lenses.
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