K.F.
Most people recommend that you let the child cry for X amount of time, go in, pat on the back, tuck in, reset a musical device, but avoid picking the child up. Then you stretch the time between going in there until they finally go to sleep. See if there are any video clips from the Nanny, she does a good job of showing how this works. The not going into the room for hours I would think would be if you have tried absolutely everything else.
Also, do you have a bedtime routine? One of the things I found with my kids was that the easiest way to get them to go to bed was to wear them out when they were up. Also, you should have a routine that signals to the baby that it is time for bed. Read a story, sing to them, rock a bit, do the bath, in whatever order you prefer. This helps them to switch gears.
Do you have a night light? There are different recommendations about the level of light in a room. Sleep experts indicate that even a bright alarm clock can be disturbing to adult sleepers so if she goes to sleep for a time, you should turn off a night light if you have one.
Also, if you are having problems with her sleeping, what time do you get her up? If she is sleeping later, get her up not when she wakes but wake her. It is easy to let her sleep late when you are exhausted but it defeats your trying to get her to go to bed at night.
Sleep was a big issue with my kids, my brother's kids were in bed by 7 every night but they were also up at 6. As they grew older, they were taught to entertain themselves with a book or toy in their bed until 7 or 8 or something, they would do this at my mother's house at well. I think mine are like me, hardwired as night people but if you keep at it, you can prevail, just be consistent. If you pick her up, she learns that if she cries x amount of time, mom will pick her up, etc.