a guy should be persistent if he really likes the girl , like trying to schedule a meeting with her 2 maximum 3 times
if after 2-3 times you have not managed to see her , then just send her a message by throwing the ball in her court
cool, trying to get the balance right isn;t it. sometimes you wonder if you'll come across needy by chasing them after they've cancelled, orthe other way that they may think you;'re not that into them if you don't pursue to a certain extent.