What I mean is that to a large extent, WW1 followed the old tactics of massive pitched battles, trench warfare and bayonet charges- although I am aware that things started to change with the use of machine-guns and tanks.

WW2 was the next big conflict, but it was a whole new ball game- guerrilla and urban warfare, high-performance fighter planes, mass bombing, automatic weapons, rockets, camouflage etc etc. Most of this stuff must have been fairly new to warfare and some of it must have been literally made up as the war progressed, with Generals finding out what worked and what didn't as WW2 evolved around them.

Was this the case?
ps- Am I right in thinking that Naval warfare went on largely unchanged, except for the advent of aircraft carriers? I mean submarines served in WW1 too.