I love putting my hair in twists because they're just as easy as braids (once you get the hang of 'em) and you can use them in any way you can use braids (french, etc.)!!!
Just a note: Your hair should be relatively long. While there's no need to have it down to the waist like me, you should be able to regularly braid your hair easily. Which, brings us to the next point: I've never worked with layered hair, but when it's braided, often there are bits sticking out here and there, which wouldn't work so well with a twist... but feel free to try!
Brush out your hair. It's really best if your hair is nice 'n' knot-free. If it's too static-y, spritz some water on it. You know your hair best--do what ya need to do to tame it!
You'll need to decide if you want one or two (or tree or four or 50 for that matter) twists. Here, I'm just doing one. So, part your hair into 2 even sections. Be obsessive about evening them out, because it's awkward to try to even them out further along in the process.
Now, twist both sections in the same direction. It doesn't matter which one you pick, but for this let's say clockwise.
Next, wrap the sections around each other in the opposite direction (counter-clockwise in this case).
Now switch your hands so they're no longer crossed over each other.
Rinse and repeat! JK, no need to rinse, but really, just repeat steps 3-5 until you get to the ends of your hair.
Sound tricky? Don't worry, you'll get the hang of it!
Tie off at the bottom.
Wear proudly! Experiment! If someone asks how you do it, simply say "magic"! I've been doing this for years, and often people don't notice right away, but they're generally confused when they realize that there are only 2 sections. Any questions? Put 'em in the comments and I'd be glad to help out!