There's a world of difference between the old-style flints and the new firesteels.

I was given one of those new firesteels that creates an incredibly hot spark. Any finely shaved, reasonably dry wood catches right away.

The old flints create a much cooler spark. If I'm using one of those (or even a Bic lighter that's out of fluid) cattail heads are at the top of my list. Pocket lint from jeans works too: I've even shaved the inside of a pantleg with my knife to make it.

One thing that's good about practicing with an old-style flint: you learn to be meticulous about materials and preparation. If anything is awry, no fire.