The only way to get it is to keep practicing. Makes a hell of a difference on the track, if you ask me. Plus, when you do it right, it has no ill effects on the transmission (just normal clutch wear). Took me a bit to get used to doing it, due to the GTI's DBW, but once you get used to it, it's second nature.
I have huge feet (14), and find when I am autocrossing or at a track, I like to wear a wide, flat shoe -- skateboard style would probably be easiest to start with. Practice doing it when STOPPED first. Put your foot on the brake pedal while you're not moving, and find the "sweet spot" where you can safely stay on the brake pedal and blip the throttle with the right side of your shoe, by quickly rocking your leg to the right. Guys with smaller feet may be able to use the proper "heel/toe" method (ALWAYS use your toe on the brake, heel/side of foot on gas), but my long legs and large hooves will not allow me to do so. If you're not comfortable doing it, never put yourself in harm's way. Practice in parking lots....whatever it takes to do it safely.
...even with somewhat smaller feet, you can probably still blip the gas with the side of your foot pretty easily. Our pedals are really close together. Just make sure you have a solid footing on the brake pedal while you're doing it. That's the most important part.
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