Waxing is the best thing you can do to keep your skis in as good of condition as possible.  There are actually small holes in the base to absorb wax.  If you don't wax your skis for a long time, modern base materials will dry out, oxidize, and crack.  As far as technique, pretty much it's been covered, but I want to say one thing.  Someone said 'wax, scrape, brush, and scrape if you want to again'.  This is correct, except for the last part.  You want to brush last.  This leaves a small amount of structure in the base so you don't get suction.  We or your local shop will sell different brushes (horsehair, nylon, brass, etc) that provide different structures for different kinds of snow.  As a general rule, the warmer the temperature outside, the harder the wax and the deeper the structure.  The colder the temperature outside, the softer the wax and the finer the structure.
Hope that helps.
Eric Peterson
Freeski Specialist
Tyrol Ski and Sports
Rochester, MN