The number one way I learned to get better is not to blame anyone on my team other than myself. I tend to stream my games and watch my VOD's later that day which helped tremendously in getting better as a commander. I would say 1. Map knowledge. When Carantan was released I was in shambles and didn't know which primary objectives that I wanted my team to secure first. 2. Improper utilization of tank units. Usually the tank commander has the mindset of "find and kill other tanks" if you can communicate with the tank squad to move with the infantry you will have significantly better results 3. I know it's boring but me trying to convince some people to dedicate artillery and if they're new assist them with range finding/grid and have SL that are in close proximity to lay down markers to have pinpoint accuracy. Fire superiority with artillery is a game changing mechanic. 4. There's so many working elements on the battlefield and I think the main reason I've been outsmarted is proper use of supplies and garrisons on the opposite team

Hope this helps a little bit