How do you tighten a bathtub handle?

It sounds a little to loose. Soon is will start dripping water down body of tap. Remove handle, remove top section of tap body and you will find a shaft that travels down through a nut. This is the packing gland. Gently tighten this up by turning in a clockwise manner and this will expand the packing out to stop leaks and will tighten up on the shaft, don't over tighten, do it bit by bit and try it as you go.