I have a slightly different take on the vaseline-cotton ball.
Although they work great, I take a magnesium bar (do this at home, before you leave) and shave off a little pile. I then open the vaseline treated cotton ball and pour some in each and roll them back up. It acts as sort of a "turbo charger", magnesium burns really hot, and works very well when whatever you have to work with is a little wet. I personally don't recommend using the magnesium as a primary source outdoors. Besides, 99% of the time, some tinder and a Bic will do the trick, first time, if you know the basics of starting a fire. I use the other stuff that I have in my little "fire kit" when resources are scarce, or the weather is just absolutely not cooperating. Trying to shave the flakes into a little pile in the tinder is often very difficult to use this method when the wind is blowing, sometimes even in a very slight breeze, the flakes just want to blow away. I put these into a freezer bag, with a couple of bags of other materials suitable for tinder, and use them when you can't find anything at your campsite.

With a little practice you can literally start a fire in a down pour. As mentioned already, practice several of the afore mentioned methods at home. On the trail, especially in the case of an emergency, is not the place to learn. Good luck, and no worries, it's a lot easier than most (non-outdoors) people think. It is so easy, even a cave man could do it.....o.k., sorry, I just had to say that...

J.