I'm a bit unusual on how I got started, but am quite like most everyone else on how I maintain my......'edge'.
I started studying wine at UCDavis, and working at some wineries. That got me started. But how I keep in top of things, is the network of fellow forumites who keep each other informed about current good buys at various shops, getting together for a day of touring wineries, get togethers, public and private tastings, etc. I also read books (Parker's Bordeaux for Xmas), subscription-only newsletters (WA), off the shelf magazins (WS, WE), and industry publications (Wine Business Monthly, Vines to Wines, Practical Vineyard & Winery, etc).