Anyone wanna offer their expertise? I kinda in a fix right now..
really depends on your budget and her preference. since taste is basically habit, what she currently wears is a nice place to get an indication, in anycase, i think modern day women have no reservations about expressing themselves, so why not just ask her ;)
This is a fun question. There are a number of things to consider here.
Is this her first "real" watch starting from a few thousand dollars? Is it an everyday smart casual watch or formal or dual functionality? What is her lifestyle, character, etc. Whilst budget maybe a concern, it is critical to think of it as a timepiece that is worthwhile, perhaps eye-catching, withstand the test of fashionability, sporty, or the understated classic yet masterpieces like the Patek or JLC for example. Ultimately, it should be a piece that she, or anyone, will like and keep for generations perhaps with no intention to sell unless really necessary.
A good start will be to browse through the homepage of those watches such as Tag, Rolex, JLC, IWC, etc to get a sense of what she likes or dislikes before heading down to the stores to have a look at the actual pieces which often times may differ from the picture. Of course, the popular high demand pieces maybe hard to see at stores due to long wait list.
Warning: Once you get started on this watch thing, it is somewhat difficult to stop at just 1 timepiece. As you grow older and appreciate more, your taste for timepieces will likely to change as well.
Very simple answer, first try to find out her choose which brand she like most and also which model or previous which brand and model number she already used after that take decision and choose the timepiece for her ....