To get more money, you have to take over neutral (or enemy) cities. These captured cities will also repair and refuel your tanks, helicopters and troops - whoever controls these basically wins the match. Think of it in terms of Monopoly. If you own all the good spots, where can anyone else go?
To add yet another strategic layer to this grid-based cake, whoever's inside the vehicles will affect how they perform. We plowed through several missions, trying out about five different groups of soldiers. Each group's description certainly paints a detailed picture, but in the battlefield, we didn't notice a difference. The only thing that was really unique to them all was their special powers.
The more you blast away enemy units, the faster a meter fills up. At the halfway point, you can opt for your mid-grade power (say, increased unit mobility and damage) or wait until it's full for the big move (usually double the mid-grade power). Some teams can see better in fog, others are adept at naval warfare - yeah, you've heard all this before. But damn does it work.