Wedding is once in a lifetime event, for majority cases though (just kidding). It’s a start of a new life for both of them. And if you have invited to any of the weddings then it is your moral obligation to bring a gift. The sad part about this event is that people consider these gifts as just a mere formality not making any effort whatsoever for choosing the right and the most appropriate gift for the new couple. 
What majority people do is that instead of the gift, they give simple plain money to the new couple which is a comparatively good option since they would need this money for starting their new life together. But that’s the simple way out. Why not go out in the market spend some time and money and choose a gift that the couple remembers and cherishes for their whole life after all it’s a matter of few hours of searching.
Coming to the main part of the article which is what gift to choose for the bride and groom and that can only be found if you carefully analyze the couple situation and look for things that you think that would need.
One of the simplest example is that you know that the couple will go on honeymoon pretty soon after the marriage, well then why not arrange them a good honey moon. The things that you can give to a couple vary from couple to couple so you need to analyze the situation very well.
The bottom line being that a little effort from your side can mean a world for the new couple.