Here are the equivalents of the RGB colour wheel...
I am surprised that if you search the web, there is little information available on working in Lab, so I guess that if you are fairly serious about colour post-processing you'll have to buy Dan's book - I did and it opened my eyes. With just a little practice it is easier to work out the elements that make up a colour in Lab than it is in RGB.
Did you know that you can change the colour of a car from
without making a single selection or painting! ? All it required was a simple curve change in the b channel (equivalent to inverting the b channel) and a wee BlendIF setting (if you are not familiar with this feature have a look at this page) - thus...
So try playing in this Lab mode and find out how much easier it is to adjust (uniform) colour casts and bring your picture alive by adjusting colour separately from lightness. While you are there (in Lab) do your Sharpening on the L channel and don't muck up the colours!