One of the most important aspects of maintaining the beauty of a piece of jewelry over its lifetime is the amount of care put into its preservation. Depending on the material used to craft your ring, it is a good idea to not wear it while performing any strenuous work - including exercising, working on your home or any other heavy labor; blows to the ring may bend its prongs, the ring itself and could even chip your diamond.
Although diamond is known as the hardest material on earth, it still runs the risk of being chipped: a hard blow to the girdle (its middle) or culet (the pointy bottom) may damage it. Aside from this, however, diamond is essentially indestructible. Additionally, its not a good idea to wear your ring while sleeping - due to the prongs potentially catching on the mattress fibers and either tearing the mattress or pulling a prong off.
To ensure the longevity of your jewels, it's best to store it in a jewelry box or an enclosed area where there are no other metals, as this could scratch your item or wear down the metal and its prongs.
For even more protection, try this surefire method of keeping your ring looking its best: Grab a toothbrush and some dish soap, mixing it in a small bowl filled with hot water. Following this, take your ring and drop it in the bowl, letting it soak for about ten minutes. After that, take the ring out with tongs - as the water will be very hot - and gently brush it until all dirt has been removed. Finally, submerge the ring back into the bowl and rinse off the soap with cold water.