It's hard to explain how to do it, but what ARon said is probably the best way to go. But don't just let the clutch out slower, let it out slightly later too. And don't freak out if the car begins to slowly roll back since if you keep playing with the clutch and gas the car will move anyway and realistically only roll back like a foot.
What some people do to train themselves is take the car onto an incline, typically a driveway, and balance the car and get it to crawl up using ONLY the clutch. This will give you much more delicate left foot control.