First get some army xp, use Army high command and stuff (i find training can be helpful) You will also want to go down the Superior firepower doctrine

This step depends on which country you are playing as. You have 2 options here
Option 1: make 14/4 (use normal artillery not howitzers)
Option 2: make 7/2 (also use normal artillery)
Option 1 is for countries with tons of man power and production power e.g. Germany
Option 2 is for countries that are still powerful (or not) with less manpower and production power e.g. Austria-Hungary
You will want to change your normal infantry division template.

You are going to need an airforce, i normally use Fighters, Airships and CAS. I also recommend going down the battlefield support air doctrine for this method.

This part kinda depends on what time it is in the game, if you want you may want to make tanks, i haven't tried this tactic with tanks as i have always won before having them researched.

Well, you are done. Hopefully you are victorious and the Entente or Central Powers have surrendered.