Starlifter's Presidential Strategy (abbreviated):
Construction of city improvements should integrate with your strategy. Such decisions are intrinsic to your fundamental long-term goals. City site and/or proximity to your capital also will affect such decisions.
Perhaps a Presidential model might help!
The worst thing to do is pull a Clinton and waffle around, randomly building an improvement here and there, usually in reaction to an event such as unhappy citizens... However, the human should still win rather handily even with the haphazard Clinton approach.
In the first years, the George Washington approach should prevail... conquest and secure a small, resource-rich area in which to start a future world power. Military forces you can gain from the land (huts) are very valuable indeed!
Early on, the Jefferson approach is probably best... expand and displace all before you, and refine the cities later.
As the game develops, the Lincoln approach will help the more powerful cities bring their backwards brethren into the industrial age, whether they want it or not. The agricultural base of the less-refined cities can be used to at least inflate their population while awaiting factories and mid-game improvements.
If a powerful neighbor threatens, the FDR approach to strategically sacrifice a few can result in the eradication of the hordes of enemy, particularly in a Democracy when the peaceful, but blind, Senate forbids a war.
If war is forced upon you, do not use the Truman approach and betray your military in the field. Do not hesitate to strike a belligerent enemy and slit his throat. Get it over with and clean up the mess later... future generations will thrive under a properly-run democracy anyway.
In late game, the Eisenhower approach is almost always best... build superhighways everywhere, and construct airports even in small cities. Build nuclear weapons and be ready to use them if necessary.
After that, a modified Kennedy approach will likely be appropriate. Divert some resources to the Apollo program to prepare for spaceship construction. Modify his approach by conducting foreign policy with an iron fist at all times. Do not show cowardice and weakness. And don't betray friends, allies, and countrymen. Personally, I always finish the game with a Spotless record, unlike the cumulative Truman, Kennedy, and Clinton approach.
In late game developments, I prefer the Reagan approach of defending all cities with SDI and all anti-missile improvements, for any populations which could possibly be in harm's way. Build a strong Reagan economy by reducing taxes and gaining 3 to 4 techs (usually FT's by now) per turn. Spare no expense to improve your scientific knowledge
build SETI. A strong Reagan economy can overcome Clinton years of indecision, corruption, and waste in late game. Always remember that Clinton's approach of leaving millions defenseless is nonsense as long as other powers still exist.
In end-game developments, I use the Bush approach of being willing to give all mankind knowledge (this will advance science even faster), yet enforce peace in a new World Order. Non-peaceful violators are crushed. Do not allow barbarians to commit Genocide in the lesser-developed areas of the world. Use your vast military superiority to crush any eruptions of evil. Encourage environmentalism *and* industial maximization in your cities, and force environmentally-friendly improvements like Mass Transit into those cities that even have a potential to pollute. Rush build; do not wait, and don't pull a Clinton. Technology is the key, and ultimately cost will be no object after the strong base Reagan economy causes a complete recovery from any Clinton-esque years of mistakes near the end of the game.
Hope the Presidential Model will help your empire!