+1 on what [MENTION=680784]bhrubin[/MENTION] said.
I'd also add that it's helpful to get one of those sheets with lists of flavors and flavor categories. Pay attention to the flavors you taste when sipping a glass and look at the sheet to put words to flavors you may have trouble describing. Do it often and you'll see you get better at it.
http://www.piwine.com/media/home-win...asting-Aid.pdf