Its often said that the style of warfare being practised in 1918 was closer that of 1940 than 1914, such were the scale and pace of advances in tactics and technology.

Probably the single most important advance was in the application of artillery, which I discuss in depth here, indeed there is an argument that artillery was both the cause and solution of the deadlock on the western front. (I'm just going to tag myself u/jonewer to keep the ModBot happy at this point)

The war also saw the introduction of mechanised armour in the form of the tank. Though I argue here that that tanks were a useful adjunct to infantry and artillery but were not decisive in and off themselves.

Numerous other innovations were implemented in the course of the war, some of which I discuss here in the context of the common accusation that the Generals were cruel, incompetent, moribund, luddites.

This is, of course, a massive subject but hopefully the above answers will give you some insight. I'd be happy to field any follow-up questions you may have.