Don’t be afraid to ask to Sommelier, they are not going to make fun of you. Practically they are paid for that, is their job to direct and help you on the choice of the wine. And usually the Somms when see that you can not make a decision they will ask you What was the last bottle of Wine that you drink, What do you usually drink at home etc.
#2 Find your comfort zone
If you know that is wine that you enjoyed in the past think about that talk about that and your waiter can find the grapes and the closer kind that will please your taste.
#3 Move out the box
Try always wines that you did not try before , or you had them once. And if you are dinning with a big group prepare your self to be flexible because not all of them will be eating the same thing, plus experimentations is very important.
#4 Check out how the wine list is organized
By paying attentions to the wine list how is organized you will be able to distinguish which are the light body, medium or full body. And find out the appellations because that will help you and finding out the varieties.
#5 How the sommelier order wine
Depends in what is the mood of the group. What is he eating, or even choose the wine and try to fit the food.
PS: Remember that the best wine is the wine you like more and not what they tell you.