Increase the vibrance and saturation of the image using adjustment layers. Increase the vibrance and saturation by using the Image » Adjustments » HDR Toning tool. Check out the various filters under Filters » Filter Gallery and see if there are any effects there that will complement your image. Remove your subject from the background by selecting the subject, and then you can either delete the background or move it to a separate layer, depending upon your end goal. Dodge and burn your image. Help the highlights and shadows in the image by using Dodge and Burn.
Another option to Sample All Layers is to make your changes directly to your working layer. This is a more destructive approach, but less resource-intensive.
Make sure that your brush isn’t loaded. Most of the time when painting a photograph you will not want any paint loaded onto your brush. Be sure that your brush is ‘cleaned’ after each stroke. Things will get ‘muddy’ otherwise. Choose a brush preset or make your own. You can make all of your own choices or start with one of the ones that come with Photoshop. You can also start with one of their brushes and then change it in the Brush Settings. All these options do is set the other options that you see to the right.
Wet: This is where you choose how ‘wet’ your canvas is. It depends upon how easily you want the paint to be moved from one place to another. At 100%, it will smear heavily. At 0%, it won’t smear at all. Load: This applies to if you were using any particular color to load onto your brush. When painting a photograph like this, you will rarely be using paint, so don’t worry about adjusting it, unless you are adding color. If, for some reason, you are adding color, start off with it set fairly low and go from there. Mix: This sets the color mixing ratio for each stroke. This applies more often to when you are adding color, as in Load. Most of the time, you won’t be needing this. If you do use it, start fairly low and see how it works for you. Flow: Flow is how much of the paint is applied when you paint. How heavily it is applied. If you don’t want the paint to move too far from the source, have it set lower. If you don’t mind how far it moves, set it higher. Adjust the rest of the options as you gain more experience.
For instance, you could isolate your subject, then put a solid color layer behind it with a radial gradient on top of it to help your subject stand out.
