Our brains aren't cameras. There is no such thing as a truly photographic memory. Some people are born with a better-than-average visual memory, called an eidetic memory, but even "eidetikers," as they are called, make errors that a camera would not. But the good news is that our brains can be trained. Whether you are borderline eidetic or have a hard time describing your own front door from memory, mnemonic brain-training techniques can enhance your abilities.
Dark Room Method
A persistent Internet rumor says that the military has been using this technique for decades to develop photographic memory in its operatives. You'll need a piece of paper with a cutout just large enough to fit a paragraph of text, a book and a dark room to sit in with a light you can easily turn on and off.
Fit the cutout in your cover sheet to the page so that it exposes the text you want to memorize, and figure out the perfect distance to hold it at so that your eyes focus. Turn off the light and let your eyes adjust to the darkness. Then, looking directly at the paragraph, turn the light on and then quickly off again. The image of the paragraph will remain before your eyes. It's said that practicing this 15 minutes a day for one month will enhance your ability to glance at an image or passage of text and memorize it instantaneously.
The Loci System
Our minds process visual and spatial data well, and are more likely to remember the bizarre than the mundane; the bizarre is what makes the loci system so effective. Use a mental image of a building you know well or a route you often walk. Write down a list of key spots or landmarks within this space. For each item you want to remember, think up a bizarre image and locate it at a specific landmark.
If you must remember to pay the car insurance, for example, picture yourself riding a unicycle with a flat tire past the park; commemorate the food you have to buy with a vision of the ingredients doing the rumba on a bench in tuxedos. Run through the sequence in your head at least once. To recall the items, take a mental walk along your chosen route.
Like the loci system, the linking method depends on the fact that our brains are much likelier to remember the unusual. If you want to memorize a list of items, make it into an interwoven story of unlikeliness in your mind. Suppose your shopping list includes hamburger, butter, laundry detergent and toilet paper. You may not remember it as a list, but you will remember the image of an angry cow sliding around in melted butter, then needing to launder her hide and dry it off with toilet paper. For longer lists, simply link each item to the one before and after it.
When introduced to someone new, try strategies that make it easier to remember the person's name. Use the name in conversation shortly after you've heard it. If you have an excuse to do so, either write the name down or ask for and glance at a business card, to form a visual image. Form an association to a memorable feature of their appearance, and exaggerate it in your mind to the point of ridiculousness: Big Nose Ned or Bonnie Blondie. (These can certainly be kept private.)