I will keep this compact but not necessarily will be comprehensive. Also this will contain more of my thoughts how I make sense of what I read than Suvorov's original lines.

1. Change in military doctrine: from "defense in depth" to "deep operation" or "Soviet Deep Battle".
The first is a purely defensive theory, it's practical implementation was the Stalin Line.
The second is a purely offensive theory, it was put in use at Khalkhin-Gol by Zhukov.
After the occupation of Poland they abandoned the first for the second. They abandoned it despite we can learn from the Finnish war that both theory and the Stalin Line would have worked great. They abandoned it because situation changed, the time had come for an aggressive war.
Deep battle calls for combined arms assaults done in depth in two phase, first breakthroughs have to be achieved then vital but vulnerable targets needs to be eliminated behind the enemy forces paralyzing them or making their resistance futile.
Combined arms is the close cooperation of branches of the military, the infantry, artillery, armoured units, air force, navy, and indeed airborne and marine troops as well. The cooperation must be kept at all level (tactical, operational, strategical), through the whole process (from the first strike until the enemy is obliterated).
This kind of operation only works with a surprise strike. Since the Red Army needs to control of the skies - for close combat support, and doing paradrops and airborne landing assaults - air superiority has to be achieved in parallel with the initial strikes (which also gets support from the air force). This only can be done by catching enemy aircrafts on the ground, if the battle is ongoing, they won't be there, they will be fighting in the air.

2. Military buildup - the creation of the First and Second Strategic Echelons.
A massive army was created with superior number in equipment (e.g. tanks, airplanes etc.) compared to the German. Stalin became the sole practitioner of power by 1927. The first five-year plan started, they had 90 tanks, by the end of it in 1932, 4000 was built (Hitler attacked the SU in 1942 with ~3500 tanks, when Stalin had ~20 000).
They exhausted every possible source of manpower to raise new units with the exception of general mobilization. Like: introducing conscription on 1 September 1939, forming new units from GULAG prisoners - most of whom were tucked away during the Great Purge, both soldiers (some 130 000) and officers, up to generals -, every units that wasn't essential elsewhere was moved to west.
The buildup in west was done in secret (so it had no deterrent value). Troop movements were covered by TASS reports that no such thing is done, they are moved only for training exercises, they are moved to winter quarters etc. The units were frequently moved by night, in dark wagons, stopped only at minor stations, couldn't leave the trains, generals often traveled in goods wagons and was misinformed on the objective.


As I searched for images I stumbled upon this blog: