[Aeraaa]

One that I like to use if I can buy my force (i.e. not a scenario):
If attacking, buy lots of light, fast firing arty. If defending, slow rate of fire, hard hitting one. Reason for that is crater creation. When attacking (and especially if you have a predominantly infantry force), the craters will be a hindrance to your troops, they will slow them down, which will make you lose valuable time. Light artillery does not create craters, so this problem is mitigated. Fast firing artillery also suppresses enemy troops quite well so if it is combined with a timely close assault, will rout enemy dug in infantry faster than heavy artillery can kill said dug in infantry. On the other hand, heavy artillery creates craters, which can slow down an enemy infantry advance, thus being great for defense (not to mention its lethality against troops in the open).


In addition to the above, buying lots of light artillery means that enemy counterbattery fire will not be able to kill them all, thus no matter how good enemy CB artillery is, you'll always have arty support of your own.