When starting a flint and steel or striker type of fire, char cloth makes all the difference in being able to actually get the fire started or just making a bunch of sparks that never catch anything on fire. Char cloth (sometimes also called charred cloth) is pieces of blackened fabric (cotton) that easily catch a spark and burn similarly to the way steel wool burns–no big flame, but a nice ember burn that doesn’t blow out once it’s lit. The spark lights the char cloth and the char cloth is used to light the other tinder.
Char cloth is inexpensive and easy to make as seen below. Old denim jeans work very well.