If you're looking for a war strategy game, look no further than Conflict Of Nations, where you'll be in charge of directing your nation's military growth and technical advancement.
Though progress in the early stages of Conflict of Nations can seem slow, your early choices will have lasting consequences. In other words, this is compound interest. Putting up airports will facilitate travel throughout your country. Having troops stationed in major cities within the country is superfluous. Because of this, stacking units does less damage.
Whenever your army size is beyond 40-60 units or the game is nearing its conclusion, you should focus your attacks on only two or three countries. If you take a defensive stance, you will be completely defeated.
Make sure the city has been annexed and is not on fire before continuing (rebellious). Once morale reaches 35%, you have the option of keeping 2-4 units within the city, or just one unit with help from patrolling aircraft.