I say try because plenty do a horrible job.
Luckily, you have me to show you the right way.
First things first, open your photo in photoshop.
Now that your photo is open the first thing you need to do is to tone your photo. There is many ways to do this but the absolute easiest way it to use Image> Auto Tone
|The before and after the autotone|
As you can see, my picture looks a lot better now but Ken's face looks a bit red. So our next step it to adjust the color balance. Like toning, there is many different ways to go about this process. Again, the easiest way is to auto color your picture. For this go to Image> Autocolor
This helped a lot but our faces still look red so we're going to adjust the color a little more. To do this go to Image>Adjustments> Color Balance
This is the screen that pops up
The best way to adjust the color is to add its opposite. Since my photo has too much red in is I'm going to add Cyan. There isn't an exact number to change it to, it's more of a feeling.
As you can see my photo looks a lot better already. To some, this is good enough. If you want to know how to further edit your photo make sure you come back tomorrow!