Write an article based on this "Grow a cupful of salt crystals. Choose a seed crystal. Attach fishing line or smooth wire. Create a new solution. Add the crystal and solution to a clean container. Check on the crystal regularly. Protect the finished crystal with nail polish."
Follow the instructions for the easy method, but use distilled water and do not use a string or pencil. Just leave the salt water in the container. Over the next few days, a layer of small crystals will grow over the base of the container.  Use a flat, shallow, wide container instead of a jar. This makes it easy to get a single crystal that hasn't merged with any others.  Epsom salts do not work well for this method. Try alum or table salt instead, or see variations below for more ideas. Once the crystals are ready, pour out the liquid and look at the crystals. Pick them up and examine them with a pair of tweezers. Select a "seed crystal" that will form the core of your new, larger one. Look for crystals that fit this description (from most to least important):  Choose a lone crystal, not in contact with any others. Choose a crystal with flat, even surfaces and straight edges. Choose a large crystal (at least the size of a pea).  Ideally, find several crystals and set each one up in a separate jar as described below. Crystals often dissolve or fail to grow, so having backups is a good idea. Super glue this to one side of the crystal, or tie it around the crystal. Do not use string or rough wire. You need a smooth surface so the crystals can't grow on the string instead of the crystal. Select distilled water and the same type of salt. This time, warm the water only slightly above room temperature. The goal is to make a perfectly saturated solution. An under-saturated solution may dissolve your crystal, while an over-saturated solution will cover the crystal in salt grains and cause a lumpy mass to grow. There are several faster ways to solve this problem, but they are more difficult and may require some knowledge of chemistry. Clean a jar, then rinse thoroughly with distilled water. Pour the new solution into this jar, then hang the crystal into the center. Store it as follows:  Place the jar in a cool, dark location, such as in a low cupboard. Keep it on a Styrofoam pad or other material that absorbs vibration. Keep a coffee filter, paper, or thin cloth over the jar to block dust. Do not use an airtight seal. The crystal will grow more slowly this time, since a little water will need to evaporate before the salt grains are forced to attach to the crystal. If everything works out, the crystal will keep the same shape as it grows. You can take it out whenever you like, but it will most likely keep growing for several weeks.  About every two weeks, pour the solution through a coffee filter to remove impurities.  This is a difficult process. Even experienced crystal growers sometimes have a crystal dissolve or become lumpy. If you have a perfect seed crystal, you might want to test a worse seed crystal first to make sure the solution works out. Once your crystal is large enough, remove it from the solution and dry it. Brush a coat or clear nail polish onto all sides to prevent it wearing apart over time.