[Japo]

Artillery is good for pounding entrenched targets but if you're attacking unentrenched units in the open you'd be wasting your shots, just roll your tanks over them.

The units up front should be unexpensive and have very good sight radius, at the start of the game your light tanks can fill that role but later you can get specialized recon vehicles.

Careful about placing tanks next to a city, if the enemy has AT it will blast your tank and later in the game the infantry also gets decent hard attack so they can damage your tanks as well. IMO tanks should be placed only where they attack, that should be open field, and needless to say they should be the first to attack wherever they are.

Infantry and tanks don't get the same bonuses defending rough terrain and specially cities, infantry is much more effective for that according to the manual.