Highest score yet posted in this thread for Tough :
)
I didn't even realize I was doing that well - I felt "behind" because I hadn't gotten much tech - even autoassemblers came late, so I didn't have much "extra time". But my economy was doing great, never short on cash. I didn't have to mechanize too many worlds, and had multiple hive/water/relic/xeno combinations (including my initial one), and just spent most of my time colonizing and linking planets without much fuss. Even had a couple mistakes that cost me a few months.
Tech tree: space folding, drillbots, replication, trade hubs (6 built), autoassemblers, starbirth (got that on the last turn, let me fix some screwed-up unmet-needs worlds).
Key learnings: luck, your economy, and minimizing how much time you spend on each planet are king.
Standard advice: avoid slipways of all kinds, use only direct connections. Eat up excess resources with trade hubs, and meet shortfalls with starbirth instead where possible. A good start, and rich planets, are key to a booming economy and high score.