Pakistan is an Islamic state and men shaking hands with women is not apriciated however if the lady her self show her hand to greet than you may also shake hand but it is quite rare.It is better to say 'Salam' incase you cant say the complete greeting i.e, 'Aslam-u-aleakum' this act is considered as act of respect and honour towards women.
In our culture, shaking hands with ladies is not considered respectful. Until and unless ladies wants to shake hands with you. Try to keep you hand with yourself. Just say 'Asalam-u-Aleikum', bow down a little and node your head slightly in 'yes'. This is considered very decent and polite.
Shaking hands with little girls under 10 yrs is considered okay. But make sure that they look 'little girls' not 'grown up girls' :-)