When you let her cry it out you will have to go in there a lot of times and do the same thing. When she wakes up go in there, DO NOT PICK HER UP, lay her back down, cover her up give her a kiss and rub her back until she is calm and a little drowsy but not asleep. Then you leave. She will start crying so you let her cry for 5 minutes and then you go back in and do the same thing over again. With each interval you add three minutes to the time you allow her to cry. Eventually she will just fall asleep because of exhaustion, but after a few nights of this she will learn that it is sleep time and you aren't going to take her out no matter what. Is she teething? Has she had a cold for more than 2 weeks, she may have an ear infection? If you don't suspect anything then go for the cry it out technique. I've done this with all my kids and have never had a problem. Be sure to do the exact same thing and stick to it no matter what. Your ability to be consistent and not waver will determine the success of it.