Kome, i find that using sleeping bag helps my kids get into a nighttime routine from a early age. So normally when they are around 2-3 months old I put them into pajamas, sleeping bag, feed them, read a short book, sing a goodnight song and then put them down to sleep. They learn very fast this way. My eldest was sleeping through the night from 7pm - 7am at 4 months old.
Mei mei took longer to train, but by 7 months old she's also sleeping through from 7pm to 6-7am and they both don't wake up for milk. If they do wake up its usually cos they're teething or ill.
At least as parents we get more rest when the kids go to bed early.
You might want to try again your bb girl this time round?