My hair went curly when I hit puberty. It took me ages to work out what to do with it, and it got curlier and curlier till I hit puberty. Then it went CRAZY when I was pg --very scary, spider's leg style, coarse, horrible. Now it is still super thick, but much less curly.
I have used a variety of products on my mane, with varying degrees of success/ dents in my pocketbook.
For super soft, wavy hair, the Kerastase shampoo & conditioner is great. I think you can get reasonably similar results with pantene (the one for dry hair).
If I want to encourage more curls, I use Loreal ultra strong hair gel -- it will be a bit crunchy till it dries, but it makes my hair boing up in nice ringlets. Use a diffuser to partially dry it too.
My hairdresser recently suggested hot rollers or a hot brush for nice big waves.
Another tip: I sometimes just straighten across the front and leave the rest of the hair underneath nice and wavy/ messy. That seems to get rid of the frizz and give it a bit of shape. I don't wash it every day either -- dires it out too much. I think half-up, half down styles can work well with longer hair too, and you can do them loose to make the curls look romantic and sultry (well, that's the look I'm going for, porbably only achieve disheveled and unwashed, but nevermind).
Agree the best hairstyle is long layers, although I really admire those who can get away with short, uneven-type styles. I think you need to have a thin face though -- I have the fat face to match my fat hair!