I have learned to punch an extra hole at each end of a NEW shower curtain, and put the hook through both holes. It doubles the strength of the hole, so you are less likely to get a tear in the first place.
When a curtain hole tears I cover it with one or two layers of clear packing tape, then punch thru that with a paper punch. It is very hard then to tear thru. In the kids bath, I did each hole like that even before I hung the curtain, to reinforce the holes.