Restaurant tip #4: What to do when the bottle comes. This is the most intimidating part of the process and where the real test begins. The key is to relax and not take it too seriously.

First, the waiter will present the bottle. You should quickly check the label to make sure it's the wine you ordered; sometimes the vintage will be wrong, for example, or the waiter will just have selected the wrong wine. Both have happened to me. If it is the right one, simply nod and say "Yep" (or "Boo-ya," if that's more your speed). If it's the wrong wine, just say so.

The waiter will then open the bottle and "present the cork." Do not sniff it. It just smells like cork. You could fondle it, if you're into that sort of thing, but otherwise just ignore it. (One exception: If you see that it's soaked through with wine, that's generally not good, as it means air probably got into the wine and could have ruined it. More on that below.) [read full article, via Kottke]