You see it in revolutionary war movies and pictures, where everyone lines up and takes turns firing. Where did this come from? How did you get others to agree to fight this way? Why was it disbanded?
They didn't exactly "take turns" firing or agree to it, the discipline and ability to reload faster than their opponents were key to the success of 18th-19th century line infantry. They would try to deliver as many volleys as possible and sometimes this would appear as if turns were being taken. These weapons were slow to reload, around 3 rounds per minute for well-drilled troops, and inaccurate enough that massed ranks were needed to deliver effective fire. All major powers also used light skirmishing troops who fought in open order to complement line infantry and screen advances etc.
http://www.napolun.com/mirror/napoleonistyka.atspace.com/infantry_tactics_4.htm
The prevalence of rifled muskets and then breech-loading rifles by the mid-late 19th century meant that all infantry began to fight in a similar fashion to the light infantry of the Napoleonic period.