A good way to avoid riding the clutch is to place your left foot to the left of the clutch. Many cars will, if you attempt this, offer an excellent block thingy upon which to rest your idle limb.

This will keep you from depressing whichever pedal happens to be underfoot - clutch or brake. Moreover, if/when you decide to crash your vehicle, you'll appreciate having something stable to brace yourself on, that you may survive to crash another day.

By having something stable underfoot, you should be able to tone down your body's desire to fly forward, assuming a head-on crash is what you're after. This will stop your head from hitting the steering wheel, and should therefore give you some time to wonder why you aren't wearing a seatbelt, as you wait for the airbag to arrive and provide some much-needed R & R for what has turned out to be a mostly stressful afternoon.

Additionally, my (Australian) driving instructor once spake thus: To disobey this teaching is to disobey the Urban Priesthood themselves. Do you hear me, child!? Such does not simply offend the sensibilities, nay, 'tis unlawful unto itself!

That driving instructor cost way too much.