Make your images pop with blending modes
Have you ever tried the blending modes? They can really add something dynamic to an image. So where do you find blending modes? When you open an image in Photoshop, you'll automatically have a background layer in the Layers palette. You won't see the blending modes until you add another layer - this might be duplicating your background by pressing Ctrl J on your keyboard, or you can add another layer with color or a gradient in it, for example.
Once you have at least two layers, the blending modes will be accessible - look directly under the Layers tab, and you'll see a drop down box with Normal in it. Click on that tiny arrow...there are many variations including Multiply, Overlay, Screen, Color Burn, Luminosity, Darken, Lighten, Hard Light, Soft Light, Linear Burn...and they all give your image a unique effect.
Most of the time, I will use blending modes in conjunction with a mask...so I attach a mask to the duplicate layer, and then I can selectively paint away on the mask to reveal the layer beneath where I really DON'T want the effect to appear.
Multiply, Overlay, Color and Linear Burn and Hard Light will darken your layer...as will some of the other effects. This is handy when you want to bring attention to your subject matter and less focus on the background - see the lamingtons as an example.
If you need to know more about how layers and blending works, don't forget that Google is your friend - there are lots and lots of tutorials online that will show you everything you need to get started. Good luck and happy experimenting! :)
Photo credits: Tamara Bauer.