What you need to do, is start reading the labels of the wine and start drinking it. buy a bottle or two a week. Read the label, match it up if you can with what the label says. You will start to taste the "buttery" or the "chocolate" . When I started working at a liquor store, I only drank red wine. Someone would come in ask for a good white wine. I would say... Is there? I realized that wasn't good for sales, so I started revisiting the whites. And a found a few I do like.
In short, read the labels and try them.