See a specialist.
Different tailors specialize in very different cuts. It's not just that Italian suits are formfitting and English suits tend to be more structured; neighboring houses in cities around the world often take varying approaches. It's important to be familiar with a tailor's house style. You don't want to be in the middle of an appointment and discover that you don't like what a tailor does best.
The traditional tailors of Savile Row like Huntsman favor strong, padded shoulders and built-up chests that taper to a clearly defined waist. It's a suit with a strong silhouette. It's ideal for a man who wants his suit to announce his presence, a man who never fears being overdressed and didn't even consider buying off the rack. Americans raised on the relaxed Brooks Brothers sack suit, might be surprised at such a formal coat. An Italian or American suit has much less structure, a closer fit, and flatters thin men, young men, and men who want to look a bit less formal.
There are, of course, happy mediums. Anderson & Sheppard, a favored tailor of Prince Charles, however, is less rigorous. Its coat favors a more natural shoulder without much padding and a gentler silhouette. That's one reason this suit maker is particularly popular in the United States.