Blindly jumping won't get you very far, so really focus on your aim (where you shoot rockets) and your keypresses while jumping. For example, be conscious when you're pressing D while doing walljumps (You normally press it after shooting a rocket), whether or not you're holding Crouch the entire way, etc.
There's not much individual style in jumping, so aiming/keypresses are mostly the same, the only real noticable individual characteristic being the smoothness of a person's mouse movements which really doesn't matter at all.
As for syncs, syncs are very dependent on ping, assuming you're playing in a server where you have a stable ping, or playing offline, start with syncs where you can look up at incoming rockets (the jump on pagoda is a good place for this) and get a feel for when you should rocket jump based on the distance the rocket appears to be from your point of view (or you can grind jump_sync).
If you're not using "cl_interp 0" and "cl_updaterate 66", I recommend it, although you can jump perfectly fine without it.
Finally... Jumping takes a whole lot of practice, eventually you'll come to a point where everything comes naturally.
This taught me quite a bit when I was starting out, especially wallpogo
happy jumping~