How did methods of warfare in world ll differ from those in world war l ?

The main difference was that World War I brought upon mankind the existance of trench warfare. Soldiers who were experiencing trench warfare were subject to horrible scenarios where they would go on days or even weeks without normal life necessities, while in WW2 trench warfare was nonexistant.

Very useful. it is to learn because history repeats itself so learning about it those mistakes not happen again.