The next biggest decision comes from picking a size. One of the significant aspects of a wedding gift is that it symbolizes starting a new life together. One needs to ensure that any gift will be able to fit into the life the couple is planning. In this case, it's vital that one not buy a rug that's too large for the area. Not only would that limit their use of the rug, but it might also be taken as slight against their ability to afford a home. Obviously you will not want to offend anyone, so it's important to figure out what size will best meet their needs.
Obviously, it can be somewhat difficult to get measurements from someone without giving them a clue as to what you will be getting them. The easiest way to get around this is to first take a measurement of a shoe you own. Next, either stop by the home that the other will be moving into or see if you can get a look at the new home if they're moving somewhere totally new. Most couples will be excited to show off their upcoming home, so this should not be much of an issue. Once you're in the house, you can walk around the rooms and measurements by keeping track of how many times you can put one foot in front of the other. While this won't be exact, it will provide measurements close enough to work for picking out the rug.
With all that accomplished, you will be ready to pick one of the best gifts a couple could hope for. The beauty of the rug should provide a clear picture to them of the hopes you hold for their future. Most well designed rugs are also so well made that it's quite possible you may well be giving them a new family heirloom to pass down to future generations. It's a gift that will keep on giving, and one which will remind them of you every time they see it.