hi there -
i have a 6 month old but he goes to bed quite early (6-7pm)... i think babies are all programmed differently so you can't make them go to bed at any set time. but i think it's really important to make sure that she is napping during the day properly. i find that if cooper doesn't have good naps he's harder to settle at night. i've also started to leave him to settle himself as well and doing the normal stuff they tell you in the books to go and reassure and wander in and out...blabla. he doesn't get really worked up - but if he does i usually will pick him up and soothe him and then put him back down (i know, they tell you not to do that - but whatever - you have to do what your gut tells you).
she may be starting to cut teeth - or going through a growth spurt (which cooper did last week and his sleep was unsettled) - so she might be harder to put down at night.
hope this helps a little bit... i think the napping part is a big key.