actually if you r breastfeeding the easiest way to get more sleep n not to wake baby is simply feed her when she is awake no matter she hungry or not. n i personally think if your baby is not sleeping through the night, then before 6mths she probably still needs night feed to 'grow'. of cos if she started to sleep through by herself before 6mths then its ok to stop the night feeding.
as for your qn... do you usually 'help' her fall asleep? if yes then probably she needs help to goes back to sleep too when she awakes at night. if she always falls asleep independently then you can check if she is too hot, too cold, wet diaper(depends on her character. my girl dosent mind a wet diaper. not even a soiled one! she can sleep for hours with a soild diaper!) etc etc. you can try covering/removing her blanket. if she is too hot or too cold, she will be able to go back to sleep after you remove/cover her with a blanket. sometimes my girl wakes, i simply cover/remove her blanket n she is back to sleep instantly. for my girl, if she is hungry, she will cry n look for my breast. if i carry her up n she stop crying n didnt even bother to look for my breast then she is not hungry. usually i put her back to cot after a while of cuddling n she is back to sleep again n wake up after 4-5hrs! so she isnt hungry! hehe.