Look about 15 degrees up from dead level when the pad launches you.
1. Walk onto the plate, looking slightly up
2. Hit space as you are launched upwards. (Imagine you're flying straight up, with the launch propelling you.
3. in the first half second or so, as you slow down, roll the mouse forward so you're not looking slightly up, but slightly down from dead level to the horizon, like you're leveling off. It takes a few practice runs but you'll get it.
I find I have the best results launching facing the desired diresction of travel, any attempt to turn at the launch usually goes badly for me. Also, speed wobble is actually a stall wobble, it happens right before you stall, nose it down a bit if you get a stall wobble.
TIP: Try switching to third person view before you launch.
EDIT: the launcher has been changed in the last two patches, now it's just simply walk straight onto it, realease the W key, then hit space at the top of the launch. I'm getting incredible glides every time now doing just that. Except when I don't.