
First of all you can cycle through land units with E or R key no need to use mouse and go over the blue dots

Secondly, you will need to organize troops into divisions (use * generals) Corps (use ** or *** generals) and Armies (Use *** generals only). Some of the * can be promoted, so pick a GOOD one and let him fight. If he survives and gains enough seniority, you will be able to promote him.
The leadership issue is a medium complexity one (very complex if you have little experience then it becomes very easy once u learn it). It's not about the rank only, and the CP needed to command each unit get summed up for a total which the rank and the number of assistant leaders may help managing.
Course if you got questions...i'm an adept player, technically AACW is the only game i play regularly.