You just called the TV repair shop and the voice on the other end of the line tells you "this is Don Smith". About 5 minutes later you tell your wife that "this guy" will be out to fix the TV in the morning. You can't think of his name although you know he mentioned it on the phone.
This happens all the time to just about any of us unless we have learned to concentrate and implant the name in our memory right at the time we hear it. To do this you first must make a habit of repeating the name back to the person. This action will remind you to store the name in your "Memory banks" each time you hear someone's name, and, within a matter of a short time the "repeating" process can be discontinued.
When you meet someone in person use the same procedure, and in addition, visualize something different, unusual from the ordinary, or "ridiculous" about their appearance, position, or actions that "ties in" with their name. You may have to put the descriptive information on one side of a card or piece of paper and the name on the other side for a while until it is imbedded in your memory permanently. Look at it repeatedly, see the "picture" in your mind's eye as you look at the name, or when you see the name visualize the "picture" you have assigned to the name.
Getting this system to work will require certain changes in your thinking and it may take several days or several weeks to become proficient. After all, you have developed a "bad Habit" over a period of many years and it is difficult to turn it around overnight.
This method also works with anything else work remembering, not just names. When you have occasion to remember something, jot it down and incorporate it into your list . . . No complicated formula . . . Just a system that works with a little concentration.