Upload & Sell: On
Ben @ 20,32,46 ... I open up color balance
I select "Shadows" and then adjust sliders to equalize them.
I can decide to raise red and green to the level of blue, or I can reduce blue and green to the level of red, or I can bring red & blue to the level of green to bring them to neutral. The combinations are quite variable, and I make my decisions based on what tonal level I want to place that area @, as well as other portions of the scene ... i.e. differing casts that might appear in "mixed lighting" scenarios.
Conversely, I will do the same for highlights, rarely do I use midtones. It's not exactly formulaic as the relationships of "push/pull" that are rendered in "shadows" effects midtones and highlights to varying degree. The same applies to mids, and highs, so it includes a degree of iterative process ... not quite the same as "click here WB", but it affords you a different degree of control.
When I'm looking for casts ... I try to find three or four areas that I'm fairly certain that they should be neutral, or at least should NOT have a given/suspected cast. If they all exhibit the same imbalance, i.e. all high in blue, then it speaks to a cast.
I don't necessarily trust a single location to be indicative of a cast, and even when a cast does exist in an area, I have to be sure to understand if it is a localized cast (i.e. reflecting green off the grass) or a global cast that is effecting all areas, from shadows to highlights. Studying the orientation of the lighting and knowing the time of day and lighting conditions is another piece of the puzzle to consider. as well.
How much to correct or leave in is of course subjective (easy @ opacity) ... but, anyway, that's how I go 'bout it.