The success of any offensive is dependant on a number of factors. An ill-conceived attack may often end with overwhelming causalities, which could put an end to your mission. During an attack, there are two things of outstanding importance: firepower and field of view. Infantry, tanks and artillery will help you break the enemies defenses. The job of armored units is to deal with bigger clusters of enemies; the artillery can help you overcome more challenging fortifications, concentrations of infantry and armor. Infantry should disable enemy anti-tank (AT) cannons and soldiers, but most importantly, they should provide vision.
You won't always be able to distinguish types of soldiers and vehicles, so during an attack, focus on destroying cannons and mechanized divisions first. This should open an opportunity to get rid of hostile infantry for your armor. If it's possible, try to assume the following hierarchy of neutralizing enemies:
- Officer/sniper (reduces enemy's vision);
- Medic (the enemy won't be able to heal their troops);
- Tank-destroyers, anti-tank cannons and infantry (eliminating them ensures safety for your armored units), artillery (if you're commanding a considerable amount of infantry, artillery is their greatest threat);
- Tanks and armored vehicles (this is dependant on the composition of your own force - if you have medium tanks and the enemy has, say, light and main battle tanks, you should eliminate the heavy units first);
- Infantry (attack with your tanks; this will let your infantry advance);
- Trucks and other types of vehicles (at this point, they will be totally on your mercy - with a bit of luck, you will manage to capture some of them).
The infantry has the best vision - almost twice as much as tanks. This is absolutely essential - without vision, your army is blind and can even be defeated by an outnumbered enemy that has better vision. If you want to carry out an offensive, use the following formation: infantry, medium and heavy tanks at the front, artillery and tank destroyers at the back. Light vehicles plus AT infantry/vehicles on sides.
Use your infantry for reconnesaince - they can take advantage of vegetation, or crawl towards the enemy. This will provide the vision needed by your tanks and artillery to be able to produce efficient fire support. Remember to turn off "engage at will". Otherwise, your scout will open fire upon spotting an enemy, which will sure end with his demise. An officer or sniper is best suited for this task. They have the best range of sight in the game; you can use the officer to detect enemies from a longer distance, if you buy the appropriate doctrine before the battle. You can use regular soldiers as well. The Riflemen are able to detect mines and have a pretty good firepower. Your next choice would be AT soldiers (only effective against light armor vehicles) or a machine gun squad. As a last resort, you can order a driver to disembark and do a recon himself. If your infantrymen were decimated, it's not such a bad idea.
You can carry out a slow offensive using artillery and a small recon team. If you don't have howitzers, you can use mortars or tanks. Send small teams or individual soldiers to observe the potential enemy positions. Turn cease fire on and proceed forward in short leaps. Start by eliminating Ats and artillery. After finishing with them, start bombarding groups of infantry, occupied buildings. The enemy will sometimes call reinforcements by firing a flare when you engage them with artillery (though it more often happens after directly engaging them with infantry). When you're convinced the enemy lines were sufficiently weakened, send in the main force. The upside of such approach is that it effectively limits casualties on your side and allows you to deal considerable damage. However, you need a lot of time and resources to complete a few of these strikes.
Outflanking the enemy is also a very efficient way of dealing with enemy if you don't have artillery or you lack scouts. In many missions you may encounter tanks and cannons that are reinforced with sandbags - they're more resistant to fire, but they cannot move. They will not leave their stations nor start moving around as long as the reinforcements are there. Use that to your advantage - bypass the area covered with their fire and you will be able to destroy them without a problem. The tanks are admittedly more challenging since they are able to rotate their turrets. Act quickly and don't let the enemy fire at you - if there's no direct route to the enemy that would permit this, use light vehicles to quickly get behind the enemy.
Infantry is perfect for catching the enemy in crossfire since it's able to take full advantage of the landscape and vegetation. This allows them to easily outmaneuver the enemy and get behind him. Always approach with the whole team and try to attack at once - that's the fastest way of eliminating a crew of a cannon or an infantry unit. If your infantry is equipped with rocket launchers or anti-armor grenades, try to approach close to the enemy and start firing - target the back and the sides of a vehicle.