Well, I'm no master either but what I've learned from a couple of sources is this.
1. You're approaching full throttle to the corner.
2. Begin braking with your right foot but leave a part of your feet to blip the throttle pedal.
3. When the revs are going down, press the clutch with your left foot and bleep the throttle keeping the brake pressure steady. What you're looking for here is to rev the engine with the engine spinning free, i.e with the clutch pedal pressed. Lower one gear
4. Release the clutch pedal.
5. Repeat until you're in the correct gear for the approaching corner.
I've seen many foot positions for heel 'n toe, but the one I've seen in a book and an Ayrton Senna video doesn't in fact involve the heel at all. There's a video somewhere in the internets where Senna drives an NSX in a pair of italian loafers and he seems to use his right foot for operating both pedals.