With short stories you have even less room to hook a reader -- one or two lines at the most. For a novel you might get half a page.
I don't think there is any magic formula.
Thinking about it, I could identify a few different tacks you can take:
- You can hook into character. Try to present something unique in the character, and hook into their personal dilemma somehow.
- Present a mystery. Something bizarre and/or intriguing enough to get the reader interested.
- Dangle a trope. Some writers are excellent at this. I recently read a Kelly Link story that hooked me in extremely well. I'd read the whole thing before I realised nothing happened. The unspoken promise (of finding the Faery Handbag) was not delivered.
- Go for the oddness factor. Present something that is so quirky and bizarre -- some sort of mental disconnect that is intriguing - that the reader is drawn in just to find out what the heck is going on.
- Or go for combinations
Now, some writers don't think endings are all that crucial in a short. Me, no matter how long they are (or short) I like to see them going somewhere -- or at least delivering on the initial promise. So I guess there is a word of warning there. That Kelly Link story was the first in an anthology. I did not read any more stories, having been fundamentally disappointed in the first. But that is just me. Others have raved about that same story and its magical quality.
So what other hooks can you think of? Or other ways of looking at hooking the reader?