I never really know what to do during negotiation time. During the first interview, I'm usually asked how much. I'm told that I should always try to push it back for the other person to make the first offer. However in matter how hard I try, they demand that I make the first offer. I don't want to aim too high or too low in fear that I'd lose out on the opportunity.
Personally, I research what is a 'standard' pay in that geographical area and then add ~15%. Nothing to lose, a few thousands to win :)