It sounds like she is ready for the "ferber method", if you are willing to try it.
I was having the same trouble with Ethan and this method worked like a charm. (We tried it when he was 8 months as well)
Your biggest mistake that you are making is picking her up. If she cries and you come in and pick her up you are letting her know that it is ok for her to cry and not sleep and she is not learning how to put herself to sleep.
They way it works is you put her to bed awake tell her goodnight and leave the room. If she cries, let her cry for 5 mins, then go in her room, pat her on the back, tell her its ok and then leave. DO NOT pick her up. If she continues to cry keep going back in and pat her on the back but gradually increase the time in-between going in her room. Gradually she will learn that crying will only get a short visit from mommy or daddy and she wont get picked up and she will learncrying isnt worth the effort and she will eventually self soothe and put herselfto sleep.
It only took Ethan one night to learn how to self soothe and he sleeps 13+ hours a night and will take at least two 2 1/2 hour naps a day. It is wonderful! (When I finally decided to try this he was still waking up every 2 hours out of habit and naptime was horrible, so I had to do something)
Here is a link with more info on this method: