Let's say you're braking before a corner.
If you are smooth with your downshifts and wait until the speed has dropped enough, i.e in the later part of the braking, you can let go of your clutch smooth. If you do it too quick your rear end may be upset.
So if you come roaring down a straight in 200km/h, you start to brake, let the speed go down enough and in the end of the braking you de-clucth and choose the gear your going to use when entering the corner let go smooth of the clutch. When you let go off the brakes you are all set for entering the corner.
It is important that you let the speed down enough so you don't release the clutch before your speed has decreased enough. This will wear your clutch and if the speed is to high you will blow your engine with or without heal-and-too.
Sometimes it can be useful to release the clutch abrupt just when entering a really tight corner to get the rear out, though.
However, Rev matching, wheter used with heal-and-toe or not, WILL when performed properly wear your clutch less.
In basic race traning the procedure is:
* Start braking
* Just before entering the corner release the brakes
* Downshift either with rev matching or releasing the clutch smooth.
* Give a little throttle and entering the corner accelerating just a tiny bit.
This method should work fine in normal traffc since you shouldn't need the extra time for braking that heal-and-toe provides.
Rev matching without heal-and-toe is much easier to learn.
Perfect time for practicing this is when downshifting to overtake.
When you can do this properly, you can start practicing heal-adn-toe but don't use it in traffic to give you an extra .5s for braking.
Do it when you have the marigin on your side.
Like Greg says once you know it''s not that hard.
And the keyword is SMOOTH.