We have just done CC succesfully.
It is by no means an easy option, and it doesn't work for everyone.
Firstly, I'd get some reading material. Christopher Green's "Babies" or the Ferber book might be good places to start.
Our DD had also really reduced her milk intake at night to 3oz once nightly, before we started, so we were sure she wasn't hungry/thirsty.
With CC you don't leave your DD to cry. Rather, you settle her in the cot at bedtime, but she should go down sleepy but awake. You give her a kiss, say goodnight, and scarper. If she cries, go in after a short interval, eg 2 mins. This may well be the longest 2 mins of your life. Go back in after 2mins, soothe and stroke DD, ideally without picking her up. But if she's in a lather you may want to cuddle her a bit, as long as you don't cuddle her to sleep. Stay only for a couple of minutes.
The next interval should be longer. We used 2,3,5,7,10,15. Pick intervals that you think you will be comfortable with eg some people allow a max of 10 mins.
We were prepared for several hours crying, but got luck, and it was never more than one hour. You will need some support, and possibly wine, to help you through it.
Most people see big improvements within 3 days if the technique is applied consistently. We set a deadline that if we didn't see improvements in 3 days, we'd jack it in.
Good luck if you decide to go for it.