You need firm pressure, it's not like striking a match. The one you have there is to my mind more of an emergency tool, if you use it regularly it will wear out fairly quickly, but it will start quite a few fires. The toothed edge of the striker you have with it isn't necessarily the best bit to strike with. I prefer other strikers than that one but it will work.
Get some cotton wool balls or pads. Keep them dry in some sort of container when you're out and about. To start a fire quickly, fluff one up a bit, lay it on a decent surface like a big bit of dry bark and cover it with other tinder and kindling but leave room for sparks to fall onto the cotton wool. Make a shelter for the fire first if it's raining and shield it from wind if it;'s windy. Strike sparks so that some fall onto the cotton wool and if it's dry it will go up in flames right away. Some people rub a little Vaseline or similar flammable grease into the cotton wool to prolong the flame which works very well but don't overdo it. Drops of oil will do the same thing. You can mess about with charcloth, tinder fungus and all sorts of things but I usually can't be bothered with all that and they can be a bit messy.
Beg, borrow or steal a decent ferrocerium rod sometime and compare it with your one.
