I had made several prior attempts, even taking a four hour class. I didn't find it helpful as we spent the entire time learning how to polish your scraper to the point you could use it for a shaving mirror, which left no time to learn to burnish properly. In any case, I already have a mirror to shave in and I couldn't, and can't, see how it would make the scraper perform better. I've read articles and watched videos but never could seem to replicate the results. This time, I vowed to keep sharpening a scraper over and over until I got it right, all day if necessary. I couldn't do it right without figuring out what I was doing wrong though.
I decided to go on the internet and look for videos. There are lots and lots, so I picked three to focus on initially:
As Curtis comments, there are 10,001 ways to sharpen card scrapers and that is part of the confusion I think. You have to pick one and try to develop skill with it. As it happened, I was initially most intrigued by William Ng's method, partially because it is at the opposite end of the spectrum from what I have been doing, so I tried exactly what you see on the video with the exception that I used oilstones rather than waterstones. I didn't joint the edge with a file, just worked to create a polished square edge on the stones. Then I very lightly burnished the edge using his two step process and, whadayaknow, I got shavings, not as good as his but shavings nonetheless! His advice happened to be just right for me because it corrected what I had been doing wrong. With all the talk of hooks, I somehow thought I needed to burnish a hook big enough to catch a salmon. He doesn't even care about a hook, just creating a very sharp edge and says that his hook is often nearly imperceptible. His focus is on a sharp corner. He likens big hooks to long fingernails that will bend and break easily. I had been creating a big, weak hook that failed quickly.
Time will tell, but the improvement was dramatic. I don't necessarily think the Ng video is the right answer for everyone but it was just what I needed to correct my error. I even did what he did and created some deep scratches on hard maple to see how quickly I could scrape them out. Amazing--and fun.