There are really two primary styles of jumping, you can use board "pop" or you can send the kite. Board pop jumps are smaller and more controllable while jumping by sending the kite can give you massive air but in a somewhat less predictable manner.
This is what you are going to do if you want to do aerial tricks. You basically edge with the board to build up a lot of force between the board and the water and then pop the board out, resulting in a jump. It is sort of hard to visualize how it works, but I guess it is sort of like making a ramp out of flat water. What you want to do is build up a lot of speed with the kite at about 9 o'clock (left foot forward) or 3 o'clock (right foot forward). One you are going good and fast, you start edging the board upwind and leaning back to maintain your edge, then pop the board out of the water at the right time and you'll jump up. These tend to be jumps of a very predictable size and with consistent pull from the kite, you will never go all that big, but with practice you'll have a really good idea of where and when you'll land. This is the type of jump favored by wakestyle riders.
If you want to go big, you need to send the kite (I'll assume you are jumping from left foot forward). Again, you want to build up a lot of speed, and again you want to start edging upwind, but you will also rapidly steer the kite overhead to about 1 o'clock right as you are releasing the board. This allows the kite to combine the lift of the kite with the board pop. Now, as you've probably noticed by now, the kite doesn't pull very hard when it is overhead, so you need to steer it back to 9 o'clock during your jump or you are going to just crash down into the water. The key with sending the kite is timing: you need to hold onto your edge until the kite is already well on its way up, then release the edge all at once.
There are lots of videos of jumping, I'd definitely recommend watch a few to get an idea of the timing and the body mechanics, it might be much easier to learn from watching than from reading.
Im trying to master my first jumps and would like to know what tips made the difference for you?
The most important tips I can think of are:
-you need a good amount of speed to jump high
-you need good edging technique and good posture (leaned back instead of hunched over)
-if you send the kite you must steer it back down to where it started or it will lose power and you'll plummet under it.
Do you look at the kite when jumping?
It is far more important to spot your take-off point when you initiate your jump. Jumping requires building up a lot tension in the lines by progressively edging upwind and then releasing that energy at once, if you aren't in full control of your board, this is effectively impossible. You need to be going pretty fast but still be in control. If you are riding in chop, this gets harder and you'll have to either look for a flat section or use a kicker. Either way, you'll need to be maintaining your edge until you jump. Once I'm in the air, if it is a big jump, I'll keep an eye on the kite to make sure I don't over-steer it, but it is also really important to spot you landing. You should be able to have a pretty good idea of where the kite is based on how the bar is pulling. I think I tend to glance between the kite and the water when I am in the air.