i'm just learning to jump now too. i've found that it's good to try it on a bit of a gust and to send the kite quicker. when i was too timid with sending it i failed to launch. there are plenty of youtube clips teaching u to jump too. just type in how to jump, kitesurfing. oh and not sure why the bar is so hard to pull in... it should be no effort.
gee its a cool feeling landing a jump!!

Have fun!