I see. So what I've written above is completely wrong? Both sides always start with the same number of clones?
No, the number of clones you have as a defender is determined by how many you have at that district. Each district generates clones but you can move these to other districts if you want to give them more reinforcement. The number of clones the attacking team has depends on the number of clones they sent from their district to attack.
And basically what happens is the first attack will almost never conquer the district, but if successful the defending team will lose more clones than they are able to generate. So you can lead a follow-up attack and lower their clone count even more. After say 3 successful attacks you may end up getting their clone count to 0, at which point you are now in control of the district.
A lot of the interesting stuff is too obscure. How do I get in on Planetary Conquest for example, or Faction Warfare? All I've been doing is jumping into matchmade games. The Mercenary and Corporation battle list is almost always empty, and when a match does show up it's only briefly and it's always full.
I imagine most people who try it are going to have the same experience.
As far as Factional Warfare goes, view the Star Map and change it from Atlas to Factional Warfare. Here you will see four corporations,
24th Imperial Crusade representing the Amarr Empire
State Protectorate representing Caldari State
Federal Defense Union representing the Gallente Federation
Tribal Liberation Force representing the Minmatar Republic
On the star map you can see which of these four NPC corporations owns which districts. You will see a "star" symbol appear to guide you to wear battles are taking place, but if you wait about a minute in the Mercenary tab of battle finder the same battles will appear in a more convenient list. Factional Warfare takes place in both EVE and Dust (instant Battles are Dust only) and you can have EVE pilots in your squad to call down even bigger orbital strikes. Right now in EVE pilots get Loyalty Points for continued support of a specific faction which they can spend on various goods. Dust on the other hand gets nothing yet, but that will surely change soon. And I haven't heard anything specifically but I would like it if there is some bonus reward if the faction you show continued support to conquers a large chunk of New Eden.
Honestly I believe Dust will be far more massive than anything Destiny will do (though I am looking forward to that too!) The problem now is partly like you said that the interesting stuff is hidden, but also partly that Dust 514 is still in it's infancy depsite being a "released" title. Like for instance right now we play on different planets but they all have the same 5 geographical properties. CCP is working on a proceduraly generated terrain system that would make each of the thousands of districts unique. Right now we only have a handful of surface infrastructures, but they are working on designing more as well as racial variants of current ones. Right now we only have temperate planets, but soon we will have lava, ice, and gas planets. Right now we Dust players don't even have access to null sec which makes up a very vast amount of New Eden. It's really hard to see how truly massive the game when so much of it looks like we are fighting on the same handful of maps over and over.