A first date, and the accessory that gives you something to do
Wear one thing with a story attached to it. It is worth more than anything that just looks good.
Built on: Clothes you have worn before and know you feel fine in.
The most useful advice about dressing for a first date has nothing to do with looking attractive, which you will manage, and everything to do with being comfortable enough to be yourself for two hours. That points at things you have worn before. A new outfit means a new set of small uncertainties — whether it is riding up, whether the shoes will hurt — and all of that runs quietly in the background of a conversation you would rather be paying attention to.
Where accessories genuinely help is conversational. One piece with a real story — inherited, brought back from somewhere, made by someone you know — is worth more than anything chosen purely to look good, because it is a question waiting to be asked and an answer that tells someone something true about you. This is the single most useful thing on this page.
The second is fidget management. Most people's hands do something when nervous, and a ring you can turn is a much better outlet than a phone, a napkin or your own hair. A plain band on the middle or index finger. It sounds trivial and it is not.
What to avoid is anything that needs managing. Long earrings that catch on hair, a bag with no strap that has to be tracked, a scarf that needs re-tying, a bracelet that slides down over your hand every time you lift a glass. Every one of those is attention spent on the wrong thing.
On perfume, since it counts: less than you think, and nothing new. Restaurants are enclosed and you cannot smell your own after ten minutes.