NEVER USE YOUR INITIAL 1000 BC TO RUSH-BUILD ANYTHING! You can make an exception if production takes you within a hair of finishing up that improvement. Spending 8bc on that Soil Enricher won't kill you. You need that money to be able to do you initial building and research.
You don't necessarily have to bring your cash reserves into positive numbers to do well. You just have to make enough income to build and research stuff in a timely manner.
Don't buy freighters - trade for them. Especially if you play on gigantic maps like I do. The freighters you get that way will be closer to other worlds than to yours.
I set up my trade routes in two phases. First I set up trade routes wherever possible, then I collect enough to implement Phase 2 - set up a bunch of trade routes with a minor power star system on the same turn. I'd rather have a minor than a major profit from my trade, and a bunch of routes started simultaneously can eventually be escored by a Trade Star (Terror Star with trade bonus modules).
I like to build these improvements in this order:
- Soil Enricher
- Habitat Improvement
- Entertainment Network (you'll be able to push the taxes waaaay up)
- Banking Center (+20% econ)
- Fusion Plant (production plus econ bonus)
At that point I usually start building critical Wonders. The Galactic Stock Exchange is a must! Sometimes I will build a Manufacturing Capital on the world that builds the GSE.
I always set taxes so that morale is 100% on all worlds. This is especially important in the early game!