>>64285843 (OP)
>logistics
introduce C-rations
>medical
tell them about penicillin
introduce the triage system
teach proper use of the tourniquet
>tanks
design Vickers MkVI type tankettes and StuH III type assault guns
>doctrine
introduce proper tank-infantry combined-arms tactics
form Commando units to conduct raids behind enemy lines
>artillery
introduce the creeping barrage tactic
expand the FOO system
teach all FDCs to use firing tables
>infantry weapons
retool for Stens and Owens
introduce base of fire and manoeuvre platoon tactics centred on the Lewis gun
>navy
design AP shells based on the Munroe effect
design and build modern carriers
>aircraft
institute formal pilot training; basically Top Gun
and teach the retards to use wing-mounted guns for fuck's sake
A LOT of the tactics we know today is the result of mistakes made in WW1 and early WW2 while attempting to discover what are the correct procedures and tactics for each situation. a lot of the above is simply using this hindsight to tell them "no you don't have to try options 1, 2, 3 and 4 to figure out what works and what doesn't, the solution is 3", and formal training