Even with marriage proposals there is a wrong way and a right way of proposing, read Best Marriage Proposal’s To do and not to do proposal list.
Most guys ruin their proposal by throwing too much money at it, and not enough thought and planning. If you’re a serious, formal kind of guy — make a serious, formal proposal. If you’re a romantic kind of guy, by all means romance her. And if both of you are daring types, she might prefer something bold and unusual. Just be yourself, but definitely make it something she will never forget.