When to toast, when to tip, when to send back the bottle-these answers will put you at ease.

When a dinner guest brings a bottle of wine as a gift, should you open and serve it?
Yes. Though there's no way to be sure of your guest's intention, wine is about communal sharing and fun. So unless the guest specifically requests that you keep and enjoy it later, serve it. Your guest will be pleased. And if you already had a wine you planned to serve, serve both. Tasting both wines will be an educational experience.

When entertaining, do you need to provide fresh wineglasses for guests each time you serve a new wine?
Ideally, yes. If more than one wine is served during the evening, it will be easier if you don't have to monitor guests' glasses or ask them to dump out a wine so you can go on to the next. That doesn't mean wineglasses need to match. In fact, having a table set with an eclectic collection of glassware is not only stylish and fun, but it also sends a message that you're comfortable, confident, and generous when it comes to serving wine.

When you are trying to get everyone's attention at a dinner party, is it crass to clink glasses?
It depends on how you do it. Banging your wineglass with a knife is pretty uncouth no matter what. But if announcing a toast doesn't get everyone's attention, the gentle chime of two wineglasses clinked together is fine.

If someone toasts you, should you lift your glass and toast along-in effect, toasting yourself?
No. The best bet here is to do nothing except look humble and appreciative. Then after everyone has toasted you, initiate a return toast by saying a simple thanks and taking a sip.

In a restaurant, is there a comfortable way to send back a wine?
Yes. It doesn't make sense to go through an entire dinner drinking something you don't like. But first you must determine if the wine is just not to your taste or is actually flawed. If the wine simply tastes unusual and isn't something you care for, choose another wine, but offer to pay for the first bottle. A wine that's flawed is a different story. A flawed wine will either taste like vinegar or have an unpleasant aroma. Most restaurants will take back a flawed wine and not charge you for it. But many wines thought to be flawed are actually fine. The real problem lies with the wineglass. If it didn't get completely clean, it (not the wine) can be the culprit. So start by asking for a new glass. If you try the wine in the new glass and it still tastes flawed, tell the waiter you'd like to choose a different wine.

Should you tip the sommelier or wine steward in a restaurant?
It depends. Most restaurant customers tip 15 to 20 percent on the entire bill (wine included), and that tip, though ostensibly given to the waiter, will be divided among the service staff, which usually includes the wine steward. However, if a wine steward has been especially helpful or has suggested wine and food matches that really made your dinner great, a small tip just for him or her may be in order. Generally, 5 to 10 percent of the bottle price is appropriate.

Is it ok to ask to taste a wine before ordering it in a restaurant?
Sure. Restaurants are happy to provide complimentary tastes of wine because they know that it will make you more comfortable ordering a glass. One caveat: It's ok to ask for a taste of wines offered by the glass, since those wine bottles are already opened. But if you plan to order a bottle from the wine list, you'll need to proceed without the benefit of a sample.

Cooking Light wine expert Karen MacNeil is chair of the wine programs at the Culinary Institute of America in California's Napa Valley. Wine prices are national retail estimates and may vary.