I think we can all appreciate what you're going through. Here are some general hints.
In the attack, flanking movements work as well in the game as in real life. If you move your forces up the extreme right or left of the terrain, you can often bypass the defenders and then take them as they retreat to their flag. At the very least, you won't have to worry about being encircled by the defender.
Use your recon squads liberally! They are there to be targets so get them well out in front of you troops to locate the enemy. They also make great defenders as they can see further than they can shoot, so they won't be too quick to give away their position, unlike the HMG squad or the command team!
Have at least 2 squads ready to provide covering fire for each advancing squad. Liberally use the "Fire" button to check ranges and fields of fire and then "Cancel" it instead of actually firing. It is an extremely handy function. Tanks work great in this roll. Let the recon find the enemy, your tanks suppress them, and then move your regular squads to flank/destroy them, or blast them with arty.
Tanks have practically no ability to see the enemy! You must support your armor with with infantry and rely on the infantry to find targets for the tanks to shoot at. They will also "freeze up" when in the line of sight of an enemy tank or ATG, so be prepared for that.
Having at least 2 mortars in the attack is very useful for dealing with enemy ATGs. When an enemy gun is spotted, bring both mortars down on it. The 8 shells they fire in quick succession will suppress the gun, if not kill it, and usually no more than two salvos from each mortar will be enough to destroy it.
When attacking, don't let your troops get bunched up in the center. As you move forward, enemy forces that find themselves further away from their flag will pull back to their rear, and can catch your advance troops from the flank.
Be aware of where the defender is likely to be. He is almost always in woods, buildings, or on hill tops, so always treat these areas as if they are enemy occupied, and check them with your recon squads before moving your larger units into range. It can be extremely difficult to dislodge the enemy from buildings, so it is better to bypass those when possible, or suppress them with one tank and then "bulldoze" them out into the open for your infantry with another.
When defending, you may want to move any armor to the rear, out of sight behind a hill or some woods until you see where the attacker's main thrust will be. You can then order a flanking move to catch the enemy's tanks from the rear or side.
Always use the "F" key in defense to check your squads' ranges and line-of-sight during the deployment phase. Make sure to hit the "esc" key after checking each unit, or they will fire immediately at the beginning of each game.
If you get totally wiped on a mission, restart it! This is really handy when you're learning. Go to "File" > "Restart Game" at the top left of your screen, and it will take you back to the beginning. The enemy will deploy the same troops on the same terrain in the same places, so this will give you a big advantage and let you try and compare some different techniques.
I could keep going on, but hopefully these hints will help you out some. Remember you can also do things like choose "Mostly Infantry" along with "Very Easy", and then buy some extra tanks yourself for an added advantage as well. And if worse comes to worse, you can always choose to fight against the Italians!