The best way to chill your martini glasses is to fill them with ice, top off with cold water, and let them sit for at least 10 minutes. Once you’ve shaken the cocktail, quickly empty the ice water from each glass and strain the mixture into it. This is an extra step, but well worth it. Any martini type of cocktail—served straight up without the cooling benefit of ice—is better when served very cold, and it stays much colder if served in a chilled glass. You can also place empty glasses in your freezer (or refrigerator) about an hour in advance.