In the first DL campaign, there are only two uncolonized planets. In the second, it doesn't get much better-there are a total of 4, and you don't have any allies. The third mission technically has 8 uncolonized planets, but as 4 of them are Class 0, we won't count them. Your ally returns to "help" you, though.

My theory is the reason your ally is so far ahead of you is because they've taken both of the available colonizable planets in the first mission, for a total of three, and left you with your one.

You might want to try colonizing-and fast-in the future. This is actually one reason why the campaign is a bad place to try to learn the game.

You might also want to consider lowering your taxes to keep approval (on a planet by planet basis) at 100% to get double population growth, until it's at a comfortable level. If you feel you can't afford to do that, keeping approval above 75% for 1.25x growth is also not a bad idea.

And, in the campaigns, at least for the first few missions, you don't really need factories initially. Every ship you'll need you should be able to rush buy, even if it's on lease, so just concentrate on labs for research.

Just my thoughts on what you've said-as I haven't actually seen you play, I can't be certain I'm right, or that any of this is helpful.

best way to learn is a custom game, not the campaign. Set the difficulty to very easy. It all about the money! Think of the starting 5,000 credits kind of a like a business investment...you should it to colonize planets, build up basic infracture..until your tax base and economy can start making money.

1) colonizing about 6-9 good planets (6+ or better planetary value) and than letting the population grow, so you have a bigger tax base mid-game. You'll need to eventually colonize that 4+ planetary value planet at right next to your capital planet...just to keep enemies away from your territory.

2) On your new colonies build 1 or 2 economic building/trade building (don't remember the name). Once morale gets to below 75 build a entertainment building. If not build one research building...and simply let the population grow..until that colony is out of the red. Build one farm...don't build more than 1 farm...unless you have bonus tiles for entertainment centers...or u simple plan to build only farms and entertainment buildings. General rule is never build more than 2 farms on a planet.

3) If one or two new colonies have bonus tiles for research and manufactoring, you should build a factory or research center first. AFter colonizing 6-9 planets...you need to quickly determine which one will be your manufactoring capital and which will be your research capital.
For manufactoring capital (the planet with bonus manufactoring tile) build 2-3 factories and start building the manufactoring capital...set that planet to focus on social production. Do the same thing or research capital planet...though u may want to build one factory to help speed up things up. Sometimes...your manufactoring or maybe your capital planet, but it not optimal.

4) Research Trade early..and pick who you want to be allies with and start trading early. It good to trade between capital planets..or planets with large populations.

5) always custom build your ships with the components you need.