For today's gentleman, it's compulsory to consult with a tailor, and not just if you're going bespoke; with a few tweaks, almost any suit or dress shirt can make you look positively Bond-ian. But what can you do to optimize your interaction with this sartorial professional—and hence your look? We asked the experts.

DO make sure things fit through the shoulders. When it comes to fit, the shoulder is the foundation of a good suit; but if the alignment is off, there’s only so much a tailor can do. Changing the shoulder means changing the measurements of the entire suit. “It’s the equivalent of open-heart surgery,” says David Coggins, editorial director at Freemans Sporting Club. “And it’s going to take a lot of time and cost a fair amount of money.” Before you commit to such a major alteration, do a cost comparison—it may be worthwhile to buy a new jacket altogether.

DO test out a new tailor on something small. Even assuming you did your research properly—that means word-of-mouth recommendations, not Yelp—it’s never a bad idea to test drive a new service. Ryan Grayson, director at Windsor Custom, suggests starting off with something simple and low-risk, like tapering and hemming a pair of jeans. But if you're diving straight in, listen to your gut. “The tailor needs to be confident that they can work with you, and you should be able to sense that right away,” says tailor Nicholas Torres, owner of Beyond Bespoke. “If you sense any hesitation, run out that door.”

DO wear your favorite suit to the shop. Showing is better than telling, especially if it’s your first visit. Coggins recommends wearing something that fits you well and reflects your style. “Wearing something that gives the tailor a sense of what you like is more helpful than giving him a picture of George Clooney and saying I want to look like that,” he says. You should also provide as much information as possible about your lifestyle and dressing habits, including how often you wear a suit and in what kinds of settings.

DO take in your shirts if they need it. Think about what you’re going to wear with the suit and whether those items are to your liking. According to Torres, most off-the-rack shirts are too long in the sleeves; you want the cuff to be visible, but not extend past the base of your watch. If you’re getting a jacket shortened, have any oversized shirts done at the same time. In fact, Grayson suggests having your tailor take a look at any item that isn’t sitting right, not just traditionally tailored pieces. “Whether it’s a trenchcoat or a sweater, if there’s an article of clothing that you love and you would like something about it changed, see what they can do about it. It never hurts to ask,” he says.

DON’T be intimidated. No one’s expecting you to be on top of the latest menswear trends. If you’re having trouble choosing between different options, ask to see an example. “Guys often don’t know how many buttons they want on the jacket sleeve cuff, or if they prefer a soft shoulder to a traditional one. But if you show them physically, they know right away,” says Grayson. Coggins recommends always asking the tailor’s advice, even if you don’t end up taking it. “A lot of tailors are a little older and they may not dress the way you do,” he says. “That doesn’t mean you can’t trust them, but it does mean you have to be firm with them about how you want to look.”

DON’T rush them. When tailors get stressed, that’s when mistakes happen. “If a tailor says he needs a certain amount of time, it’s always best not to hurry him,” says Torres. “Let him do the best quality work he can.” If you have an event coming up, don’t take your suit in at the last minute. Torres recommends allowing for a one week turnaround, and two weeks during wedding season when alteration shops can get backed up.

DON’T have an attitude. If you’re not satisfied with something, bring it up straightaway; a good tailor will find a way to fix the problem. Just don’t freak out or lose your cool. “If you’re rude to a tailor, they’re not going to want to work with you again,” says Torres. “Next time you come in, they might not suggest so many alterations.” On the other hand, building a positive relationship with your tailor can really pay off, according to Coggins. “It’s kind of like being a regular at a bar. If you’re a good customer, they’ll be appreciative, they’ll turn work around fast, and they might even give you a discount every now and then.”

DON’T feel obliged to tip. Torres says that while it’s not unheard of, tipping is neither necessary nor expected. But if you’re happy with a tailor’s work, you can show your appreciation by telling him he did a great job, paying in cash and—the ultimate compliment—referring your friends. “Word of mouth is his business. If you like your tailor, it’s almost your duty to share him,” says Coggins. “And you know men. If they have a tailor they’re proud of, they want to tell other people.”