There are so many ways to alter the color of an image in Photoshop. In fact, there are so many different ways, it's easy to simply just give up trying new ones, and just stick with what you know. In truth, I can't really argue with that. Just to name a few, there are Curves, Vibrance, Saturation and Hue, color balance, Variations, and Channel Mixer. Then, when you want to remove color, you have desaturate, black and white, and grayscale. If your feeling lucky, you can go with Auto Color or Auto Tone. Whew… but despite all those tools I just named, I didn't even tell you about my favorite one of them all.
Whenever I see tutorials talking about color corrections, I see them using curves or the variations tool. It's funny to me how they never use the Selective Color tool. However, when you use it, you have an ability to make selective color corrections without needing to create detailed masks. It gives you the power to grab a specific color range, and make your adjustments in CMYK instead of RGB, which also allows for better color control, than any of the other tools in the Photoshop arsenal.
For example, if you wanted to select the greens within an image, you would normally need with either use Color Range, or Quickmask. Then you would use curves to manipulate the RGB Color Model, carefully balancing all three colors at once. However, with the selective color tool, you can just grab the greens and start manipulating them with a CMYK tool, which can be an easier color space to work with than RGB. Additionally, the tool lets you control colors in the lights, mid-tone and darks as well, all from one tool.
If you need to do color correction, but do not have the technical skills to use Photoshop Color Correction Tools, there are other software options available. For example, OnOne Software PhotoTune, a stand alone option. Simply load up the software, and start using a "More" or "Less" system that walks you through the standard image retouching process. Another 3rd party solution is PictoColor iCorrect EditLab, which also offers an easy to use color correction interface.
If you have an image editing project that requires extensive color corrections, there are many options available for you to explore. Whether you need to make overall changes, like removing a yellow color cast from fluorescent lights, or specific changes, like the blue in someones shirt, there definitely a wide variety of ways to achieve your Photoshop Color Correction objectives. You will just need to take some time to explore all your options, and learn which ones will generate the results you are looking for. On the up side, there are many different approaches you can take. On the down side, it will take you many hours of research to play with all the tools that are available to you.