Summarize:

This could be ribbons, string, beads, paper crafts, or small objects. Keep in mind that incorporating heavier objects into your mobile will mean you must be more careful about your placement. Weight must be balanced on each side to keep your mobile straight. In addition to your decorations, you will need a wooden embroidery hoop, yarn or string, masking tape, and scissors. A hot glue gun is also useful but not necessary. If you are using objects that are heavier than paper or plastic beads, try to have a few more than you think you may need in case you must add some for balance. There will be a metal clasp that will likely need to be turned counterclockwise to release the two hoops. The inner hoop will be used to hang the mobile, while the decorations will be attached to the outer hoop. Keep in mind that the visible portions of the hoops in the finished mobile will be the outside of the outer hoop and inside of the inner hoop. How long you choose to cut these strings will depend on how low you want your mobile to hang. Try to make sure that each string is roughly the same distance from each of its neighbors. They should create four equal sections of the hoop. Finalize placement before securing the knots. Position the knots on the outside of the hoop and cut off the excess. Make sure that the distance between the hoop and the end knot is the same for each string. Check that the knot is secure. It will need to be strong enough to support the full weight of your mobile. Hold the hoop up by the knot to make sure it hangs horizontally. If it is uneven, determine which string must be corrected to make the hoop hang flat. There are two different ways you can secure the decorations depending on their type.  Light decorations, such as those made of strips of paper or ribbon, may be attached permanently using masking tape or a hot glue gun. Simply decide on placement somewhere along the circle and secure them to the inner side of the outer hoop. Heavy decorations must be attached to the outer hoop with string. Cut a number of strings slightly longer than you would like your objects to hang. You may make them all one length, but staggered strings of different lengths will look better. Attach one end of each string to each decoration, either through adhesive or by tying a hoop around the object. Separate objects into pairs of roughly the same weight. Tie the opposite end of each string around the outer hoop. Make sure that each paired item is directly across from the other to create balance. This method may also be used for light objects, such as beads or origami, which you would prefer to hang rather than attach directly. With lighter objects, balancing them is not necessary. Hold the mobile by the top knot to make sure the hoop hangs horizontally. If it does not and you used heavier objects, you will need to readjust them to achieve the right balance. Determine the source of imbalance. It may be caused by objects that were not matched properly or ones that were not spaced correctly. Loosen the knots to reposition the objects. Reattach the hoops and check again. Repeat this step until your mobile is properly balanced.
Figure out what you want to hang on your mobile. Gather your materials. Separate the inner and outer hoops of the embroidery hoop. Tie four strings to the inner hoop. Tie the opposite ends of the four strings together. Attach the decorations to the outer hoop. Reattach the two hoops to finish your mobile.