The main memory technique that is used by memory champions is called anchoring
and descends from memory techniques used by the Ancient Greeks (see http://en.wikipedia.org/wiki/Method_of_loci
for more). It takes advantage of your brain's overwhelming abilities in visual and spatial processing to create often absurd and always interesting mental images that are very easy to remember.
A Memory Journey
is a journey through a place that you are familiar with (such as your house) where you use items as anchors
for the things you need to remember. As a bonus, you can remember these frontwards and backwards (like a wonkavator).