Adjustment Layers and Layer Masks in Adobe Photoshop
Probably the most useful tools I’ve found in Photoshop (I’m using CS4) are the adjustment layers! They allow a huge amount of control over the image, without changing the original, and can be changed at any time in the future. It’s wonderfull to be able to turn them on and off, to see exactly what each change does, as it modifies your image.
I’ll be adding various tips and tutorials on using these great tools, over the next few weeks (or months/years?), so check back every now and then. With a bit of luck, something that will help your own images will show up here!