WWII in itself was an amazing period of when minds and machine came together to change the way wars were fought. The type of battle tactic used by the Germans was known as the blitzkrieg.
It started out with bombings from bombers and shellings of artillery on roads, airfields, and jam communications by bombing communication centers (Pictured here are Ju-87s)
Next came the panzers and other tanks who broke down fortifications and front lines of defense (pictured below is a PzKpfw IV Ausf D in Semois on May 12th of 1940.
Then the infantry took positions and pursuing the enemy so enemy cannot put up a formidible defense. Blitzkrieg, meaning "lightning war" meant that speed was the key and this tactic worked very well. The reason is that with Blitz, the Germans could catch their enemy on unawares and quickly defeat them.
Edited by Slickmeister