starting from the line

Hi, I'm new to this board, but I've been reading some posts and people here seem to know their stuff. I'm also new to driving stick shifts, and I find that starting from a standstill is, as everyone says, the most difficult part. I was wondering if y'all have any tips for 1) getting off to a smooth normal speed start, and 2) launching at a pretty fast speed.

For normal starts, I've been either letting the clutch out slowly to the engagement point and then easing on the gas, or I've been hitting the gas as I was letting the clutch out. I do okay, but I'd like to know how to make my starts smoother. My car jerks if I don't give it enough gas, it seems, so if it does that I know to add a little more gas and depress the clutch a little bit more. Also, just a follow-up question, but do I need to slowly let the clutch out in a continuous motion, or is there a point when I can just let go of the pedal quickly?

As for starting at a fast speed, as people racing would do, I have no clue how that's done. Do you rev the engine up to a certain level and then just quickly let your foot off the clutch when it's at a certain rpm? If so, is it advisable to do the same sort of thing, only at a lower rpm, for normal starts?

Thanks in advance for your help!