The war-theater includes land, sea and air. This will force you to set-up fool-proof defense installations to protect your armies and industrial properties against any kind of thread.
On land you'll have an extensive number of buildings and vehicles at
your disposal. You should try and build a base as quickly as possible.
Different types of buildings will offer you several opportunities. As money
flows in you should try to put it to good use.
The vehicles can be used for reconnaissance, defensive and offensive purposes. Make sure that you build factories because these will enable you to produce additional vehicles. The best strategy is to build vehicle-groups that combine the strengths of all individual vehicles. For example, a group could consist of four tanks, two scouting jeeps and one radar-jammer.
In the air you'll have helicopters, jet-fighters and transportation
air crafts. Of course they need appropriate airfields to land on and for
Air crafts can also be grouped. For example to make sure that an important transport plane is protected against enemy fighters make sure that you send some fighters of your own. By grouping the fighters and transport plane you make sure that the fighters will stay near the transporter.
On sea you may build extremely powerful task-forces. They may consist of transport ships, battle-cruisers and aircraft carriers. Again, you can group ships to form strong groups. To build ships you'll need harbor facilities.
Vehicles from all "media" can be grouped to create large battle groups. Finally, you can even create groups of groups, giving you maximum control over your forces.