If you find yourself scudding, rather than getting upward lift, you'll probably find your starting the kite too low down the wind window. Jumping does take some getting used to though.
You're two main options are the pendulum jump, as described in previous response, running with the kite and turning upwards and back on yourself, or a stationary jump, which I find much easier. Depending on the level of wind I try a couple of approaches. If loads of wind and you can actually get the kite up in the air, take it right to the top, then you only need bring it down a small amount, and the wind will just take you up. If not loads of wind then best to fly slightly lower down, across the window and then upwards.
As I say, loads of practice is all you need, and also a good idea to try and get somewhere you'll see other flyers doing jumps. Much easier to learn by watching and trying to repeat.
Best of luck with it.