Reading your work out loud is as simple as it sounds, but the benefits to your work and the relationship you forge with readers is immeasurable. The tiniest bit of tin-eared prose that actually looks "right" on the page reveals itself with a foghorn blast when you're reading aloud. What seems in your head like a witty turn of phrase becomes a mouthful of awkward pauses. And these things are never difficult to fix! Don't let it discourage you when you try it and realize how incredibly bush league your work can be. That's the first step to improving it.
I'm not fond of the sound of my own voice, but it was worth overcoming my initial resistance to access one of the finest tools currently in my arsenal. Read it aloud, comb out the knotty bits, and know you've done your work proud.