Attach three more magnets inside the cup, directly beneath the original two magnets. This will create a stronger magnetic field as well as hold the top magnets in place. Unfold one end of each paper clip and tape them to opposite sides of the cup, with their unfolded ends down. Rest the ends of the coil in the cradles formed by the paper clips. Adjust the coil and the clips until the coil stays balanced and centered while spinning freely on the clips.
Good balance is important in getting the motor to operate well.
Once you have determined how long the projecting ends of the coil must be to rest in the paper-clip cradles, you may trim off any excess wire. Use the clip leads to connect the battery or power supply to the paper clips, connecting one terminal of the battery to one paper clip and the other terminal to the other paper clip. Give the coil a spin to start it turning. If it doesn't keep spinning on its own, check to make sure that the coil assembly is well balanced when spinning, that the enamel has been thoroughly scraped off if enameled wire has been used, that the projecting end has been painted with black pen as noted, and that the coil and the magnet are close to each other but do not hit each other. Keep making adjustments until the motor works.