I would have put this in a "Color correction" area of the forum, however, there isn't one that I can tell and since what I am going to describe is done in LR, it probably should be here.
I am sure there are many on this forum who have learned a great deal about color correction from Dan Margulis's "Professional Photoshop, 5th Edition," like I have. I have found it indispencible for getting photos to be "believable" in color first, before doing any increases in contrast, or saturation/vibrance. For those that may read this post and not know what the technique basically is; well, you basically take readings of known colors in the info palette of PS and see if those numbers line up with what you would expect a reasonable person to believe the color really is. Additionally, Dan believes that since the most reasonable way to introduce contrast is via curves, you must decide what part of the image is most important and ensure the steepness of a luminosity curve covers that range.
That being said, I have learned how to get the most of the LR in using this technique and here is the step-by-step:
1) Upon importing into the Library of LR, don't do any adjustments except defaults. It is important at this point no changes to the original color of the original occurs.
1.5) If you have a noisy photo, anything you do in the Develop module makes it worse; therefore (unless you are happy with the luminance noise slider results in LR), use the Develop module color noise slider to remove any color noise, first, then go into Photoshop and remove the luminance noise with the noise filter or your favorite after market noise removal product. You may want to do a quick initial adjustment to white balance in LR before doing this step, but the sliders are always there anyway upon returning to LR with the resulting PSD file. You may try do the following steps, then go into PS to remove noise and sharpen, but it is really up to you and the areas the noise is prominent. If noise is only in insignificant areas, then I wouldn't get concerned about this step.
2) If you had to perform step 1.5, then go back in LR; if not, you should still be in LR. Adjust exposure, recov, blacks and fill light (be careful with fill light) to get the photo exposed the way you want it regarding luminosity. Don't use brightness or contrast sliders. Leave them at their default settings.
3) Begin to take readings using the white balance dropper, but don't actually use the white balance dropper by clicking on areas until you perform this step of taking readings. Moving the white balance dropper around, write down (since you cannot record various readings in LR) the readings of areas where you know what the color must be, as best you can. Take readings of all areas of significance where you know what the color must be. If that is 2 readings (like white and black for a tuxedo) then fine; but if for a very colorful summer day at a flower garden, take 10 if you have to.
4) At this point (and you are still in LR), either you need to open PS and open the color palette in PS, or Dan's book to understand what RGB values yield types of color (i.e. green, yellowish green, greenish yellow, red, reddish yellow, etc...). Ideally, we would have LAB and CMYK value abilities, but those may be coming in a later version of LR. Using the color pallet in PS LR, you can use the other color spaces to generate the colors you expect and see in RGB how close your readings are. I know that LR uses percentages instead of 0-255, but those of you used to CMYK, it is simply 50% equals 128 lightness in RGB. On this step, in conclusion, you are simply using PS as a tool to help you get the colors changed in LR from your color readings you performed with the WB eyedropper.
5) After understanding whether your colors are reasonably within the range of expectation, or out of expectation, you begin to use the WB dropper in LR to make an initial correction by clicking somewhere you think should be gray (in the 70%,70%,70% range in LR for RGB). Use the left side of the module that changes in the picture as you move the WB dropper around. As you click and the color appears better, check your color sampled areas again for accuracy and see if they are closer to the expected color or not. If closer, you should use the WB sliders to fine tune until it is right; if further away, then you need to keep on with the WB dropper until you move in the right direction, at least.
6) Now, after you have fine tuned with the WB sliders, some areas may still be out, or not enough in the direction you want to go, due to things like conflicting color casts, etc.... Some of these can only be fixed in PS with masking techniques, however, try the HSL sliders using the dropper type instrument that you can pinpoint an area, click and move up and down directly in the photo and the appropriate sliders corresponding to that color will move left with downward movement, and right with upward movement. If you are trying to change a color, you may best be served starting with Hue sliders. If you need more of the same color, use Saturation. If you need the color lighter, or darker, use Luminance. It doesn't take long to focus on an area, try H, S, or L and see if your colors get closer to what you want. Remember, H changes color, S increases or decreased that exact color in terms of very little color (therefore white) to very intense, and L moves from gray (no color) to the actual color.
7) At this point, go up to the curves in the Develop module and mouse around the significant part of the picture to see where on the curve it lies. When you have this understanding, then move the curves to ensure the significant area is in the steepest part of the curve.
8) If you know about how to intensify color through LAB and need more control over contrast, at this point, move into PS and covert to LAB color space profile and perform curves based on Dan's book for simple curving.
9) Size, Sharpen and Print.
10) Enjoy!
Let me know please if you have better suggestions for I am always seeking to learn.
Pat



