There are two schools of thought; some couples like to shop for the ring together while others prefer the element of surprise. Know your lady and approach the situation accordingly. Although personal preference should be your guide there are a few general basics; You should always buy the best ring you can afford You should concentrate your money on the center diamond You should buy a ring that 'wows' you every time you look at it (don't approach engagement ring shopping like looking for a sensible pair of shoes!) Don't make your mounting too fussy or trendy Choose a mounting that showcases your center diamond properly When sizing your ring remember if it is a wider shank you may need to go up as a much as 1/2 a size