Sun Tzu's Art of War is a must for all who wishes to secure themselves from a faux pas on the battlefield!
My own experiences, (first as the horrified defender and the thrilled assaulted):
Russian paratroop pioneers are horribly efficient in their use of flamerockets, in particular against soft targets (of course).
In the case of having mortars with smoke, these are (unless you have Thermal Imaging and the enemy doesn't) best used to screen
supportive weapons, and not the infantry that you are currently dealing with. At least, when smoke is deplyoed, its goal should be to offer your forces a secure flank, so they may themselves flank.
The main goal of a mission should never be to "Take those hexes" or "Smash the enemy as much as possible", seeing as these encourage maneuvers that put your soldiers in more than their fair share of harm's way. Instead, it should be to develope a sound plan for all your platoons, that will eventually lead you to these hexes and those enemies.
Oh.. and don't just sit on the hexes when you've won'em. Artillery is doomed to come a-splashin'.