I hook my live shrimp through the head. They usually are alive for about 20 minutes. You should have a bite by then if not move on to different bait or tackle.
The best way I have found is: I used a Mustad bait saver hook (it has 2 little barbs on the shank) bite off the little pointed tip in the middle of the tail fan and insert your hook. The bait will swim natural and will not come off with a hard cast.
I put it right behind the head or carapace, I think that's what its called. where the hard part of the head stops and the tail begins. top to bottom so the hook is facing towards the end of the tail once it is all the way threw the shrimp. Keeps the shrimp alive and i think it is what causes them to flick their tails more making them look more lively in the water. Hope this helps, good luck.