Blitzkreig Tactic

Summary
The Blitzkreig Tactic is a strategy that I came up with and later recognized the similarities to the tactic utilized by the Germans in both world wars. The basic principle is a strong mechanized force that can survive a hit and take out a CC with few casualties. This strategy works well whether you are fighting a player, or an enemy where the other team has left.

Early Game
This plan needs a strong economy to back it up, so try to get as many power and nuclear plants as possible. Always defend power plants that are under attack, because defending one is cheaper and easier than making a new one. If you feel comfortable, you may begin the mid-game phase before the 10-minute mark.

Mid Game
If you didn't start early, this is where the second phase of this plan begins. Once you have a stable economy that is over 100 CPM, create a base of operations in a defendable area that has a Tank Factory, a Barracks and a Fort. You will not need the Barracks if you choose to use Juggernauts, but it will be useful to your allies. Next, get a Soldier House, a Tank House and one or two Research Centers at your starting base. It is crucial to tell your teammates where this new base is so they can defend it for you while you work on your army. Research the soldiers up to the maximum (14) and tanks up to one below the maximum (10) research Humvees and if you think you will have time, Juggernauts (Juggernauts work best for this, but Heavy Soldiers are fine too). If you are on a map that needs you to cross an ocean to get to your enemy, two Transport Planes and two Transport Ships are a great choice for moving your force across this ocean. Note that if you are on a budget, you can forgo researching Humvees and the final soldier upgrade in favor of using a Medi-Truck.

Late Game
And now you can begin amassing your troops. Using your Fort or Barracks, create 12 of your soldiers of choice. You will also use the fort to make your Humvees or Medi-Truck. Use your Tank factory to create 10 tanks (Heavy and Light both work) and create an air force if your allies are still building their armies. Load your soldiers into the Humvees or Medi-Truck, and begin moving towards the enemy base. Once your entire army has arrived, attack with your tanks (and planes if you made them) first to soak up damage, and then send in your soldiers. If you used humvees, do not unload your soldiers, as this negates the purpose of the Humvees as a shield for your soldiers. Send your troops into the middle of the enemy base, as defensive buildings will be able to hit you if you are close enough to hit the CC.

End Game
Once the main enemy base has been taken care of, abandon the rest of your forces where they are (unless the enemy has another base somewhere else) and use planes to wipe up any remaining hostile locations (these will be primarily economy buildings).

Options
You can use Heavy, Light, or a mixture for tanks and planes. You can use Juggernauts or Heavy Soldiers as your infantry force, and two Humvees or a Medi-Truck as transport. You can use Space Fighters instead of planes as your air, but they are not worth the price unless you need to chase down a navy after the main battle. You can replace two of your tanks with artillery if you want to soften up the enemy position before you attack, but this will need to be planned in the early or mid game stages since artillery needs to be researched. You can also substitute two of your soldiers for snipers or medics.