This topic can fill a whole day in a classroom at a racing school. To answer the first question, you don't
heel and toe to accelerate, you can double clutch to upshift to save your syncromesh in the tranny, especially if you are skipping a gear. Your just briefly puting the tranny into neutral to let the gears spin at the same speed before pushing the clutch again to shift.
Peacy expained what the two are but in racing you should do all your shifting and most of your braking before the corner and heel and toe helps for smoother shifting while your braking at the same time. You can brake slightly in the first 1/3 of a corner (called trail braking) to help put more weight on the front tires to grip more.
Rippley, the techniques for rallying include heal and toe, left foot braking, and hand brake turns.