You have a great photo. You have a great design. One problem: the photo doesn’t “go” with the design.
The solution is to change the image in Photoshop to more accurately match the colour scheme of the design or, more commonly, to match the client’s or brand’s colours.
In the above example the final image (on the left) was changed from the original image (on the right) to reflect my client’s corporate colours.
There are many different ways of doing this in Photoshop. For the different segments of the umbrella I cut around them using the Pen Tool (P) and, after feathering the resulting selection slightly to get rid of hard edges, I filled a layer with the red or the orange and set the layer’s blend mode to Color Burn. Linear Burn also works, as does Color. Play around with the layer blend modes.
However for the dress I used a different technique. After isolating the dress in the same way, by making a path with the Pen Tool and featuring the path’s selection (Select > Modify > Feather… (CS3); Select > Feather (before CS3!)) by 2 or 3 pixels, I changed the colour slightly using Hue/Saturation. Go Image > Modify > Hue/Saturation… (cmd/ctrl-U) and move the Hue slider.
To get the client’s or brand’s corporate colour, read the RGB or CMYK values by hovering over them in Photoshop whilst looking at the Info palette and see if you can emulate those values on the part of the image that you are trying to colour. Do this in order to get an accurate colour match.