Want a quick, sure-fire way to make them stop? Take in a sudden, semi-deep breath and hold it for at least 15-20 seconds, and then let go.
9.999999999999 outta 10 times that will work. The reason is b/c the nerve that stimulates your diaphragm and other muscles need for inspiration to contract is really "finicky" and can make your diaphragm twitch. When it twitches, you start to hiccup. By holding your breath, you force the nerve to send constant signals and it straightens itself out.