sounds to me like the tinder is too big and maybe not dry enough. Leaves and twigs are no good, although I suppose if the leaves were really dry and then crushed up they might work. You really need something very fine. If the twigs are dry you might get it going if you were to scrape them to form some dust. Have you got any birch around where you can peel some of the loose strips off, they go up well.
It really does need to be fine to take a spark, or something like char cloth, tinder fungus etc.
To get more control of your sparks try only using the end 1/4 - 1/2 inch of the fire steel, hold the steel as close to the end as you can allowing just enough room for the blade to scrape.