How Do I Get My Baby to Fall Asleep at Night?

My seven-month-old does not respond to crying it out to fall asleep at night. After four weeks of it, she still cries 1-2 hours each night. She has no trouble falling asleep for naps during the day, but night is a whole other story. What other method should I try? Why might she be struggling so much?

Suggestion:

Doing the 5 S's really works!
1.Swaddle (tight wrap in a blanket)
2. Swing (Swinging front to back or side to side)
3. Sound (White noise or shsh in ear)
4. Side (lay baby on their side)
5. Suck (pacify)