A web clamp is an ideal tool for repairing wobbly tables, chairs, and stools. Its long nylon strap conforms to any shape and can be wrapped around all four legs at the same time. If you don't own a web clamp, just grab a length of rope.
After applying glue to the weak joints, wind the rope around the legs twice, then tie it off. Slip a long wooden dowel or stick between the rope strands and slowly rotate it around in circles. Keep twisting the rope tighter and tighter until the joints on the furniture are drawn together. To prevent the rope from unwinding, rest the stick against one of the stretchers or rungs.