Finding these is easiest if you sort of memorize the mint mark position. It's pretty high up there and pretty much in the middle between the 9 and 5. Then look for the shadow D. On Coop's example it's obvious, but on later die stages it can be more tricky.
Here is one I found last night. Note that if you are too close to your computer screen it will be hard to see, but if you back up four or five feet the D is obvious. Just one of those easier to see with less magnification rather than more.
