I'm not a Photoshop image editing genius, seriously. I only started using this program less than 2 years ago and I'll probably use the wrong terminologies and everything.
Anyway, here is how I edit my photos!
STEP 1: Open the unedited picture in the image editing software you use. I use Adobe Photoshop CS4, but most this tutorial should work for most programs.
STEP 2: Create a curve adjustment layer and click "Auto" (one of my favourite buttons). Drag the black line wherever until you like how it looks.
STEP 3: Create a vignette. Go to Layer > New Fill Layer > Gradient...
And change the settings as shown. Click on the colours to change them and ensure one side is transparent!
Make sure the opacity is NOT set to 100% or it will look horrible.
STEP 4: Create another curve adjustment layer and shape the individual red, green and blue layers as shown.
Remember to change the opacity! Different photos require different opacities and curves.
STEP 5: Adjust the brightness and contrast.
Save your image :)
By the way, you definitely shouldn't follow this exactly. The layers differ for almost every image I edit. I hope this helps, anyway!