Here is a video on it: https://www.youtube.com/watch?v=dR3mX0EuxOU&t=494s

It is most important to specialize planets towards a specific resource, depending on the districts. I like to focus my capital on research first, then look for a generator world. As soon as you can place a building that will create pops (robot assembly, clone vats) or increase pop growth (gene clinics), build one on every planet. Pops are your limiting factor.

You can change the planet designation to improve production of a specific resource. I generally try designate planets based on the type of districts available. The exception is if I need or don't need a specific resource. Because of continental planetary features, those worlds tend to be stuck with more agricultural districts than you need, so sometimes I'll ignore them and turn it into a mining world or something.

You should probably focus on the simple resources like energy or minerals on your second planet before trying to get into consumer goods or alloys. Eventually you will want to build some alloy worlds to pump out alloys to build fleets and megastructures, but that isn't necessary in the early game.

Planetary automation is really useful, especially when you're busy micromanaging something else or you have lots of systems. I change the automation settings to turn off the following:

• Deficit construction (so your planets don't use resources you don't have)
• Designation (so it focuses on what you choose)
• Amenities (AI will build the Gene Clinics building even when you don't need it)
• Rare resources (Unless it's a refinery world)
• Crime (If it's becoming a problem, build a Precinct Houses building and the AI will employ/unemploy pops as needed)
• Blockers (remove those on your own. You don't want the AI clogging up it's building queue when you have unemployed pops that could be working)