Let’s start with colour. A white shirt is classic, but it can be demanding because it heightens contrast and highlights any fit issues. If you know the event will be long and intense and you want to look fresh, light blue is often more forgiving for complexion and lighting. A piece I like to recommend for sonia dress code is Koszula Azzurro, because its calm shade makes tie selection easy and does not shout in photos.
The collar matters more than you might think. A Kent collar is the most universal, while a spread collar (wider set) looks better with a fuller face and a wider tie knot. If you have a shorter neck, avoid overly tall collar stands, because they will swallow your proportions. One more real-life note: many men button their collar fully only for a moment, then loosen it. If the collar is too tight, you will do it automatically every five minutes. Choose a size that allows two fingers under the buttoned collar.
A tie in sonia dress code should be elegant, but not theatrical. Silk with a calm weave, grenadine, a fine micro-pattern all work well. If you want to get it right without overthinking, go for navy, burgundy, or deep green. A particularly reliable example is Krawat Classico, because it adds a sense of order and works with most navies and greys. And if you prefer a softer character with a slight sheen, take a look at Krawat Seta, especially for evening events.
Pocket square? Yes, but keep it restrained. With sonia dress code, it should read as a detail, not the centre of the look. The simplest white linen square, folded straight, does the job. If you want to add colour, choose a shade that echoes the tie but is not identical. That way you look like someone who understands the rules, not someone who bought a ready-made set.