There are two parts to my madness, I mean method: Association and Repetition. I'm sure you're familiar with each of these. Now I will give you a formula for using them most effectively. Association starts with the first handshake. Begin as follows:
When shaking hands with someone for the first time:
Next, associate their name to someone, somewhere, or something:
The more ridiculous here the better, e.g. do they have boyish-cut bangs, wear "stuffy" clothing, talk like a hillbilly, or think they're funnier than they really are? If you haven't had time to establish a personality, the handshake will tell you a lot, e.g., limp, firm, sweaty, etc.
Gabriel: As an example, Gabriel was a very handsome young gentleman I met, with a strong physique and eyes blue as the heavens. No-brainer for me here; "Gabriel the Angel" was forever his name in my mind (of course I just referred to him as Gabriel in class.
Donegal: There was that guy named Donegal who of course immediately drew to mind the city in Ireland. I know nothing about "Donegal" but did perceive that his green-colored sweater could be made of wool. Green and sheep, Ireland, Donegal; I hoped it would work. And it did!
Rusty Nail: Take for example my brother-in-law Rusty Nail (yeah, that's really his name). He has red hair and a "to-the-point" personality (which I noticed upon our first meeting.) He in no way reminds me of a rusted nail in looks or personality; in fact, the only hair on his head right now is a small military regulation mustache. But, his mustache is "rusty" colored.
The second part of this mad method is of course, Repetition.
Well, that's it. Easy, huh? Will following this method be mistake-proof? NO. But you can use your mistakes to your advantage and usually to the delight of the subjects. I make a mistake with every group, and they always get a good laugh out of it. It's actually kind of important. Otherwise they may consider you a "show-off" because you can remember names.
Common mistakes
George: There was this wonderful gentleman in one of my classes that I accidentally called George (to this day I can't remember his real name). He corrected me. When this happens, I have to make a second association and do it out loud in front of everyone to help it stick better in my brain. Usually, just the fact that I made a second/better association and did so publically ensures I'll remember that name forever. However, the next time I spoke to him, I called him George again! Well instead of acting embarrassed, I just said, "there is some reason I want to call you George, but I don't know what it is so, may I just call you George?" They almost always say yes and actually feel special. The class laughs every time I say "George" and it makes for a fun day.
Janiero: This beautiful lady's name I saw in writing before I was introduced. So, I tried to pronounce it with my limited education of Spanish (shjaw-nee-air-oh). She explained that it was pronounced Jan-air-oh. So then I thought, "Oh, like Rio de Janeiro!" Then, when I went to write her name on the board, I spelled it wrong (ei vs. ie) and I was still mistakenly softening the pronunciation of the "J." I then admitted publically that her name would probably continue to stump me the rest of my life. This gave everyone great satisfaction to know I did not consider myself perfect AND that it was their group that would be remembered as the one that stumped me. Now the truth is, I've since then remembered how to pronounce AND spell her name, but in class I would always refer to her as the lady with the name that defeated the "world-class name rememberer." Again, fun was had by all!
Mark: Now how hard could this be? But the first time I forgot a guy named Mark's name, I said "Sorry, it must be because it's the same as my ex-husband's." The audience loved this SO much that I've started using it as an excuse for just about any gentleman's name in the group that I forget! Then, I say no, that's not really true, and try to come up with another association.
The common denominator between all these associations is, have fun at your expense. You will endear with rather than offend those whom you forget.