How does planetary approval get calculated? Edit
Approval uses the following components:
fMorale = fCivABilityFactor + fBaseMorale + fImprovementFactor + fPlanetMoraleBonusFactor - fNegativeTreasuryFactor + fPlanetQualityBonus - fTaxModifier
Base Morale starts at 100. Population then decreases that base morale. The higher the population, the lower your base morale.
The player's Morale Ability is taken to the 0.75 power (a morale ability of 100 will add 31.6 points to your planet's approval rating). EDIT: The previous statement appears to not be correct in 1.0D1.008. If the previous sentence was true, every planet would have the same fCivAbilityFactor ("+x% from native ability"), but that turns out not to be the case. I believe that the player's Morale Ability is multiplied by base morale, then the total is rasied to the 0.75 power. Or fCivAbilityFactor = (fPlayerMorale * fBaseMorale) ^ 0.75 - a close match to the observed bonus in-game.
Planetary improvements such as Entertainment Centers are added up and then multiplied against the base morale. For example, if your base morale is 100 and you build an entertainment center that adds 15% to morale, then you would get 15 points for this. However, since population is always > 0, your base morale is almost always less than 100.
MoraleBonusFactor is based on what things are unique about the planet such as from events.
NegativeTreasuryFactor comes into play. The longer you are in debt, the more of a negative impact it has.
If the planet class > 10, you receive 10 points for planet quality bonus.
The player's tax rate affects approval as well. It is a non-linear progression. At first, the tax modifier is simply the tax rate to the 1.02 power. Example, a tax rate of 20% would result in -21 points to your approval. But this modifier grows. At 70% it is to the 1.1 power meaning you lose 107 points. This number is then divided by 200.
Sample list of relation between taxation and morale v1.0D1.008
If this seems complicated it is. In the course of play balancing, the sausage factory is tweaked and tweaked to reach that hard to define "fun" factor.
During the early beta of GalCiv, the approval rating was very straightforward. For every 100 million colonists, one unit of "desire" was created. If that desire wasn't filled by either the player's natural ability or planetary entertainment, that desire went unfulfilled and that 100 million colonists would be categorized as unhappy. Take the number of unhappy colonists divide it by total colonists and you have a nice, straight forward, easy to understand formula. It also would have meant dumbing down the game and taking out a lot of neat elements and so it eventually evolved into this.
As complicated as this looks, it's actually fairly straightforward: As your population grows, they have needs. Their expectations are magnified by your tax rate. Fill their needs with entertainment and/or a high morale ability and you are fine.
My approval rating is low! What should I do? Edit
Take a step back and decide for yourself how important it is. If your government type is a dictatorship, which it is as you start out the game, what should you care? As long as they're paying taxes and your population is growing, you're set. There is no difference between 51% approval and 99% approval. If your approval is at 100% on any particular planet, its population growth rate doubles. However, if your government is republic, democracy, or federation, then there are 4 main steps you can take to increase morale. 1. Lower taxes if possible, don't lower it too much or your economy will sufer. 2. Increase your technology in the Xeno Entertainment. 3. Use a transport to take part of the population off the planet with low morale if there is more than 10 billion people, or if you consider it overcrowded, to a less crowded planet. You could also invade an enemy planet and increase morale. 4. Build entertainment centers on the planet. Of course, low budgets, wars, invasions of your planets, and so forth all effect your approval rating, so attempt to avoid it.
What am I supposed to research? There are so many different things, I can't even imagine what they will do... Edit
Although the GalCiv2 tech tree is large, it's simple in structure. You have a series of linear branches, each focused on a specific type of improvement (finance, morale, production, ship speed, weapons, etc.). There are no examples of techs with multiple prerequisites, and the branches never come back together late in the game.
So generally, you should pick an area that you would like to improve and then research the next 1-3 techs in that area, then pick another area and repeat. One research pattern that is useful is to research several social improvmenents in a row, such as production, finance, food and morale. As you complete these technologies, queue up those improvements to build on your planets. Focus your production on social, and while they are building, research a number of military improvements such as speed, miniaturization, weapons, and defenses. After the social improvements are done, design new ships using the military improvements and focus your production on military. While the ships are being built, you can research some more social improvements and then repeat the cycle.