You must consider many important factors when on it. The first thing to note is to choose what suits her personality and lifestyle. If your partner leads a simple lifestyle and is more of a classy person, a solitaire diamond ring with side stones or a tension set diamond ring will be perfect.
Next thing that you must think about is her profession; make sure that the diamond ring setting that you choose is perfect for her work culture. In case she indulges in strenuous activities, it will be better to choose a ring that does not employ delicate band, prongs, or any other sharp edges.
Another factor that you must consider is her finger size. In order to get her exact finger size, you can take any of her existing rings and check for the size markings on the inner band. Otherwise, you can seek help from any of her close friends or relatives.