Very Good
This game is great, and for people having trouble you should limit yourself to only two anti-tank structures and two barraks for the first missions. After that head on to gold for money. I recommend you build defence until your money gets to $100. Then build units. If you have everything, you should get two anti airs, two anti tanks, an economy building, research, and a lazer or a phazed array radar, depending on your army. Once you are fully upgraded and have stable funds, replace the economy building and research with airports or launch sites. Replace the anti tanks with factories andblow the enemy. Like Hank514 said, you have to win slowly.
PS: You shouldn't bother to upgrade infantary unless you want to use them or you have nothing else. I recommend tanks instead of infantary.