-Turn on airplane mode on your iphone before going underground on a subway or anywhere you know you will lose signal, not only will it save you battery life, but once you are in an area where signal can be attained, it will come back instantly when you turn airplane mode off.
I learnt this one after I experienced a few times where my iPhone wouldn't regain signal for a few hours after getting off the subway.
-When buying anything off a shelf, grab from the back, newer merchandise is always stocked from back to front, especially at grocery stores.
-never buy seafood that's on special at a restaurant, the only reason they put it on special is to get rid of it before it's spoiled.