How to trade commodities to become rich.

 
The Trader is the strategy most players begin with.

You locate an Ore port and a Goods port in sectors next to each other.
Trade back and forth (using warp moves) until either you can afford a hull upgrade or the port's prices are no longer very good. Repeat often, and upgrade whenever you can.

When you're engines are large enough to real space move (this varies on the galaxy size in each game, usually anywhere from 27-33) between two well stocked ports start trading using real space moves instead of warps. (Be sure to buy a Fuel Scoop before you real space trade.)

Be sure to have the maximum amount of Emergency Warp Devices and an Escape Pod at all times to ensure survival. Focus on upgrading your Hull, Energy, and Engines. Everything else is good for combat or colonizing. Your military technologies can be zero as the Emergency Warp Devices are your primary means of survival.

Trading allows for a quick rise in score, and allows players late to the game to catch up. However, the lack of planets virtually ensures that you will lose in the long run.