A couple of other tips:
- Try to use Earth planets to create humans where possible. Although robot -> wheat can be useful, population affects your final score so you want to have a human bias.
- You can also create humans from ocean world, wheet + ore = human, which is useful, and if your human flows to a mining planet then then its a two-way flow immediately.
- The settlements that create happiness, I think for jungle it's humans and goods, for earth its computer chips and goods, these upgrade aren't great because it's hard (maybe not possible?) to upgrade the planet to prosperous or rich, and because the planets don't provide resources it can limit your expansion potential. I would only do this if there is no other option, like you have a jungle at the edge of the map.
- Try to get three resources into every marketplace. Four resources have no effect, so three is the max. If you have two spare resources on their own then it's still worth creating a marketplace for them but you may be able to route a third resource from somewhere using the upgrades.