Hunter-killers. Best for eliminating enemy armor but extremely vulnerable to AA.
The "eyes" of the team. Use buildings for cover and AT (Anti-Tank) squads to ambush armor.
Every unit has a special ability (e.g., Smoke Screen for tanks, Sprint for infantry). Use these constantly; they are on short cooldowns and often save your units.
This is especially true for Support . Once your artillery fires, the enemy will see the "streaks" and likely counter-battery you. Fire and move immediately.
In team play, you must pick a specialty. Each has a specific responsibility: