Finx, Ziaheart's way is awesome, I happen to do it myself too. I only collect more keys because my job allows me to do it. And what Firn said, there are only 4 key fragments each hour, so there's no way to find "more" as you put it.
Because I've seen so many variants of the list of places where you can find the fragments, I'll just say this: Click every link in the main tab. It's safer this way, and really doesn't take as long as it seems. It's good to form a pattern. For example, I start with the Main page (click on the big KofK sign above the main tab), then I click everything in Help section, then in My Account section, Games section and so on. I'd finish with the Disclaimer, but I never found anything there, maybe it's IP thing. Some pages don't give me anything at all, so when I learned this with time, I just skip those pages, so it makes everything even quicker. I end up finding all 4 fragments most of the time.
It happened to me a few times, that I couldn't find the 4th one, so I went to my Bookmarks or Subscription pages and clicked a random thread. If you scroll up and down the topic, you may be able to find the tricky 4th fragment.
That's all the "tricks" I know and recommend
Edit: And of course go through all the Shops. And you might want to check the Art Gallery sub-pages too, though this one never worked for me personally
