Start with a structured piece
The blazer sets the level of formality. A straight cut and shoulders that do not pull make it easier to go from a meeting to your commute without building the entire outfit around a trend.
Fasten the button, raise your arms and sit down. A jacket that cannot move with you will be hard to wear, even if it looks good in a mirror.
Add a fine knit
A fine knit softens the formality of a shirt and is easy to take off. If the blazer is dark, keep a light or muted colour near your face.
Check the thickness under the sleeves and at the shoulders. A bulky knit can distort the jacket and restrict movement.
Keep accessories useful
Earbuds take up less room than headphones around your neck and leave your collar clear. Their comfort depends on the tips and fit; it is not only a style choice.
A watch can echo your strap colour or stay almost hidden under a sleeve. Check the dimensions and whether you really need its notifications.
Test the day, not just the photo
Walk, carry a bag and sit for a few minutes. Shoulders, collar and trouser length are easier to judge in motion.
If a piece has fewer than two possible combinations with your wardrobe, put off buying it and start with what is truly missing.