I have found that I also have trouble if I try to light the tinder by holding the sparlite like a lighter and flicking it with my thumb. When I hold the sparklite with my my thumb and middle and other fingers and strike with my index finger I get much better results. It usually only takes me a couple strikes to get the tinder lit this way.

As a sidenote, I prefer to use the dry outer bark of a grape vine as my fine material bewteen the tinder any whatever fuel I am working with. I make a nest of it and get it burning from the center out. It will become a smoldering hot ball of fire and light damn near everything I have messed with so far. This stuff also works great with charcloth.
I still mess with real flint and steel from time to time, just to make sure I can.

When I make charcloth, I generally let it go until the jet of gas catches fire and burns out on its own, then remove the tin from the fire and let it cool. It works for me. <img src="/images/graemlins/wink.gif" alt="" /> I also use the method of holding the charcloth over the flint and then striking against it with the striker. Even the tiniest spark will catch on good charcloth with this method. When you are first starting out it might be good to add and extra peice of charcloth to your nest of fibers just to give you more fire than you need. It will speed your success. Once you get some practice in with this you won't need to do this anymore.