Yep.

First, don't scrape with the edge of your knife blade. Bad hiker. *wags finger* Use the spine of your blade if you don't have something like the piece of hacksaw blade that was mentioned. Personally, I like a file.

Don't strike with the edge of your knife blade. The spine of a bi-metal hacksaw blade, or an unknurled (I think that is the word I want) part of the edge of edge of the file.

Have the filings go into another, beefier tinder as others have mentioned. Think of the magnesium not so much as tinder as a solid accelerant. I find the biggest edge it gives you is that if you tinder is less than perfectly dry, the heat of the magnesium is still enough to get it going, while the spark alone requires tinder that is pretty much bone dry or has something like petroleum jelly in it.

Put the forward edge of the mag block down level with the tinder, on the firelay, with the ferro rod pointing just "below" the magnesium. With a solid, brisk stroke, scrape down on the ferro rod, holding the scraper at about a 90 degree angle. Have tinder and small kindling at hand.

Test your striker before you put it in your kit. It needs to have a good edge on the corner you'll be striking with, not something rounded over. I've always had better luck with carbon rather than stainless steel, as well.

And practice.

And another tip. The search function here is a little quirky, but it will find most of threads we've discussed this on in the past.