The concept of Layer Blend Modes can make your eyes glaze over...mainly because there's so many of them. In fact they are super easy to get your head around and not only that, they can help you fix things like under or over exposure in 10 seconds flat. What's not to love? So hop aboard the Layer Blend train and let us take you and your photography to a land where even the dullest shot can be spruced up to look a million bucks.
You'll need Photoshop to use these skills, but you don't have to be an expert by any means. If you're brand new to Photoshop it would be worth doing the Basic Introduction to Photoshop right here at the Photography Campus as well.