There are many ways to edit a picture and so many different ways to do it. I am going to help you how to create a great photo.
Step:1 First we will adjust how bright the picture we will do this by going to image, adjustment and to brightness and contrast. You can mess about with this to get the right colours for you.
Step:2 next you will want to highlight her face by the icon that says edit in quick mask. Highlight her face to use as a new layer.
Step 3: Now we will be able to edit easier. We will now use a tool called the spot healing brush this will sample her face and replace it. Then highlight and rub. This should be a rather long process
Step 4: once you have done that Photoshop will blend the skin to make the best shade.
Step 5: Quick mask her eyes (you should know how to do that) And repeat.
Step 6: Then go to adjust and curves. Mess about with this for a bit and you will get a feel on how to use this tool.
Step 7: Do this process for what you need/ want to do with the picture.
Ihope these steps will help you change the colour of a photo.
This is ok but you don't really explain how you perform the task here, you need images to help you.
T: Please finish this task fully explaining how you use the tool using step by step images.