If she is close to her friends or sisters, they likely know her exact preferences.
A durable, everyday ring (like a 2mm+ band) is often better than a "show piece" that might be too fragile, as discussed by Reddit users . buying a ring for your girlfriend
If you are unsure of her exact taste but want a surprise proposal, buy an inexpensive, simple ring and tell her you will go together to pick the final one. If she is close to her friends or
A common, though not foolproof, method is that a woman’s ring size is often close to her shoe size. The "Solid" Story Arc buy an inexpensive