Beginning ice skaters have trouble finding the sweet spot of the blade and that is why their spins may be unstable at first and/or inconsistent.
How To Find the Sweet Spot When Learning to Spin On Ice Skates:During spins, the skating foot should make smooth and even little circles on the ice. The circles' tracings should be on top of one another. If a skater's weight is too far forward, the smooth and even little circles cannot be achieved and the skater may end up on the blade's toe pick.
Once a skater finds the sweet spot of the blade, the tracings on the ice that make the circles during the spin should be double line tracings. If there are single lines made on the ice as the skater circles and spins, the skater is too far over on an inside or outside edge, and that will also cause the spin to stop.
Practicing spins over and over again is the only way to find the sweet spot of the blade and to master spinning. Also, relaxing during a spin will help a skater spin continuously on the sweet spot of a figure skating blade.