There is too much to know about photoshop...its very...general. There'd be learning on how to create brushes, how to create shapes, etc, etc...its easy to get overwhelmed then lost, especially when the things you learnt can't be applied to your pictures.
My advice about learning photoshop is to come in there knowing the specialization you'd like to learn, and ignore all others. Even when you specialize on just pictures there are a lot of things you will never need. My suspicion is that you'd probably be very happy knowing several concepts and use them on all your pictures :
- Layers window.
- Dodge/Burn tool
- Curves.
- Adjustment Layers --> Vibrance.
Just these 4 things (but you have to know them very well) - and ignore all others, and you should be able to get a picture like the one you wanted, provided that the raw shot you create looks like one freesoul creates (which is really, very well done). Photoshop still works with the old garbage in, garbage out
. Do you have photoshop?