Trust the Rat.
Generic tip #1: You can die in a heartbeat if you rush into a Sector unprepared! Know what's in there before you go in guns blazing!
There are three stages to the game: The Assault, Standoff and the Endgame. You will get rushed early, so defend your planet. After the iniail assault you need to secure a powerbase and grab planets for tech and a neutral zone. The enemy will also tech-up if left alone! You need to tech FASTER than they do, or crush them before they become too powerful.
Get your homeworld producing your strategy! Be it Tech, Fuel, Scanners you need your production base aligned to your plan!
Get out there and get a buffer zone of explored sectors around your colony, you need to see hostiles on approach so you have time to jump back and defend your main repair and refuel site!
Alien planets hold new tech, so a strategy of high fuel, fast speed can work wonders here. Take and hold new worlds against the odd aggressor, then tech tech tech!
How powerful is powerful enough? Smashing the regional Capitals means you need to know if your flagship is strong enough. Probe cautiously with the jump drive locked for an escape route.
Defense in Depth
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_Factories
While your population can outproduce both factories put together, Factories will triple the repair rate for your hull and armor.
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_Fuel
For one research point, go for this upgrade, running out of fuel is certain death in combat. The amount of fuel is related to how much power you have allocated. Unused power also does not consume fuel.
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_Research
There are many ways to win in EA, but pick ONE and go with it. Back it up with solid tech picks by focusing on offense or defense. Torps or Lasers. Exploration or Combat.
MORE TIPS LATER, HAVE FUN!