Starting a fire is a work of art. A lot of people can accomplish it, but very few can do it well. And when it comes to using a ferro rod, the people who are successful every single time are simply masters. You can learn the technique by watching the master, himself, Dave Canterbury.

So, to summarize, don't use your knife blade. Just in case you missed that: DON'T USE YOUR KNIFE BLADE! You will only damage it and will take off far more of your ferro rod material than you  actually need. In a survival situation, this kind of waste is simply unacceptable.

Using the back of the blade works far better, and even a stone will yield greater results if swiped properly. The best advice of all, though? Practice, practice, practice.