Compression 101 by endquoth is the kind of tutorial I wish I had access to back when I was trying to figure out how compressors actually work. It covers the topic from a drum n bass producer’s point of view, taking a somewhat less technical route and offering just the kind of insight that most beginner EDM producers will probably appreciate.
Apart from being an interesting read, it also offers a set of great illustrations which will help you visualize what actually happens to your sounds as you apply more compression. Recommended for anyone struggling with this important aspect of music production!
The article also recommends using s(M)exoscope, a neat freeware oscilloscope VST plugin by Bram@SmartElectronix. I second that one, and would also like to point out another freeware alternative, the great Oszillos Mega Scope by Benjamin Shulz.
Thanks to endquoth for his great effort on creating this tutorial!