Namely, make everyone as happy as you can. Of course, I make no claims to having mastered the game's nuances, but so far I've had little luck with repression. If I ignore religion or housing, for instance, my presidency comes tumbling down. This is partly because some soldiers get upset if you don't provide religion and housing. Ironically, I've also had problems with soldiers who demand liberty for the people.
Unhappy soldiers lead to military coups.
In my later games, I plan to screen the military of bleeding hearts and using a cadre of soldiers who can be kept happy and loyal by appealing to a few select motivations. This is actually where Tropico is a very rich and deeply satisfying game. The motivations of the people are laid bare. But in Tropico, 58-year old Analisa Bonilla dies of pneumonia in a banana patch. Her body lies face down in the sun.