sorry for not reading the replies you've already had so I maybe repeating some info.
When she wakes at night, ignore her at 1st, but if you do go in to see her, don't turn any lights on, don't start talking , dont do anything other than lay her back down , check her nappy is ok, and put the blanket back over her and walk out. Even if at 1st you have to do this 20 times a night, she will soon get the message.
Each time she wakes, wait 5minutes longer before you go in, do this for a max of about 4nights, then after that reduce the number of times you go in.
Be persistant and firm with yourself and this new routine.
If you use music to get her to sleep , try and wean her off this aswell. Otherwise babies learn the only way to get to sleep is by listening to music and this will include when she wakes, expecting to hear it. Which is not fair on either of you.
Also try giving her a smaller lunch and a bigger evening meal , with her evening meal being no later then about 90mins before she goes to bed, in otherwords if she goes to bed at 7, start feeding her no earlier than about 5:45 , give her a bath after her evening meal,this not only gives her the message that bath time is followed milk and bed and gives her tea time to settle then after her bath followed by any milk feeds she still has , to top up any gaps in her tummy lol.
However as she gets older , some young children get a new boost of energy after a meal, but its not very likely at this age, and a play in the bath followed by a routine she should be ok.
She maybe waking up becuase she is hungry or just wanting attention.
Also she maybe getting too much sleep during the day or too late in the afternoon, so try and make sure any afternoon sleeps she has , she is up by about 2:30pm.
Also for her evening meal esp, make sure she eats a filling meal of very high quality, no rubbish.
I've been a nanny for over 15years and have seen many families that have got themselves and their babies/children into such bad habits, that with a few simple changes in their routine and habit can all have a better nights sleep.
I hope this kind of makes sense, good luck and just be firm with yourself and remember this, you've heard of the saying "Anything for a quiet life"?
Well with my nannying work, I use my own saying of " Anything for a quiet life today makes for a noiser life tomorrow".
In other words, "anything for a quiet life today" ( giving the children what they want today just to keep them quiet) "just makes for a noiser one tomorrow ( they will carry on with the same bad behaviour knowing it will get them what they want) .
Good luck , let us know how you get on.