She may have a lot going on developmentally - it can be such a common age for sleeping disturbances to crop up. It's hard work, I know.

Apart from doing the things that soothe her, I don't have any suggestions unfortunately. We have found the only way we can soothe Jacob is to rock/pat/cuddle/stroke etc - he simply needs that comfort and to know you are there. I haven't found doing these things has created any problems - if anything, it just means that during his waking hours, if he's upset and wants a cuddle, then he comes straight to us and has the confidence to explore his surroundings whilst knowing that we are always there to help him if he needs it.......

Good luck!