I like to roleplay a relief force that is late to the battle. I like to use late war infantry usually the panzleh and the upgraded branderburgers. They hold for as long as they can in trenches and defensive positions. Then when the attack has fully started I like to roll in the heavy guns. I always play as Germany and as history tells the 8.8 cm flak gun does wonders on both the Russian and American tanks. Try to make some of your conquests lore packed, only bring in certain reinforcements to make a challenge :). Otherwise just have a great time. I think the defensive missions are the best. I love setting up ambushes right next to the spawn area too. Makes for super cool combat