R.O.
We used a truncated Ferber method. Here's a link to the Ferber method explained: http://www.babycenter.com/0_the-ferber-method-demystified... I don't think any sleep training is recommended until 4/6 months of age. Our pediatrician, Dr. Todd Wolynn, is a sleep specialist, his is a truncated Ferber method. This is what he advises in a nutshell:
Have a pre-bed time routine, say goodnight, lay baby down still awake, walk out even if screaming and crying, close door (mainly to muffle the sound) and do not return. This might mean hours of screaming on the first night. For nap time, limit it to one hour, after one hour the nap is over even if baby screamed the whole time. At night, baby will eventually fall asleep, trust me, even if its' several hours, by the 3rd-4th night it will work like a charm! When baby wakes unexpectantly during the night or nap, wait five minutes (will seem like an eternity). After 5 mintues, go in and calmly check to make sure nothing is wrong (diaper dry, not sick, or tangled in blankets) do not pick baby up to calm or do more than is necessary to assess well being of baby. Once you've established baby is ok, tell baby, "go back to sleep, I love you, I'll be right downstairs (or where ever you'll be)." Walk out of room and close the door, leave baby scream until he/she falls asleep.
Sounds awful, but trust me it is worth it. The hardest part was fighting with my husband about sticking to the plan while we listened to the screaming. It's awful to listen to your baby scream and choose to do nothing. Just remember, doing nothing is doing something when it comes to sleep training!
Dr. Wolynn's method worked great for us. We have a 2 1/2 year old and we could just lay him down and he would go to sleep. Our 5 1/2 month old is doing it now. She's doing great!
As far as your neighbors, put her to bed around 7:30 PM, even if she crys a lot, the worst won't be in the middle of the night. And if she cries all night, trust us, it will only be 3-4 nights, by the time your neighbors get around to complaining, she'll be sleeping through the night!