It is hard to win because in real life, modern Mech combat is exceptionally deadly and fast. The game models that well. You can start by learning the various weapons systems and reviewing how the Army and NATO deployed them. Also, review the Soviet formations too. Rule of thumb is that NATO owns the night and quality, Soviets have mass and diversity of weapon systems and artillery. METT. Mission, Enemy, Terrain and Tactics and Time too.
Spend a lot of time reviewing the terrain. In the real world units would find cover and LOS advantages naturally. in the game you have to be meticulous on ranging your weapons... NATO has longer and better ranged weapons but you dont want to get into a knife fight with a soviet juggernaut either. fire and maneuver and stay out of the Arty. Once you engage, reposition.
Take out the soviet AA well before you send in the helos or fixed wing. this game is deadly to helos (which i think is a bit overdone personally as in the real world they would pop up and dive behind the treeline avoiding missles). Reserve your air strikes for critical moments in the battle instead of wasting their potential. Take out enemy HQ once you spot it. Keep your HQ moving too.
For your Arty, dedicate one unit to Counterbattery and one on call and the third for targets of Opp. Move them after each firing too. Otherwise, have fun, replay every battle and enjoy losing as it is realistic. :)
Seek, Strike, Destroy, 3/63 Armor, 2nd Bde, 3ID.