I read this and dived in!
http://forums.galciv2.com/104908
In my experience, the computers are pretty easy by default; I just started building factories and whatever else seemed good (a lot of research buildings) and now I'm the most powerful civ with everyone else (including the Drengins) sucking up big time. I traded some techs with my diplo ability (playing as Earth). So I would say dive in for the first game unless you want to try a higher difficulty to start.
Big things I've learned (but remember I'm only starting myself so some of this could be misleading):
- The Ship Hull tech line is vital for military; until you get medium-sized hulls, you can't make any real combat ship. Military = respect.
- Miniaturization makes ship parts smaller so you can fit more on the same sized ship, so that's good too
- If the tech tree is overwhelming you, check out the list in the upper-left and pick something that looks good for the # of turns. Even if you don't fully understand what it does, it's not a big deal on the default difficulty since no one else really seems to know what they're doing either.
- It's good to get those resources before other civs call "dibs" (borders are always open in space as far as I'm seeing)
- trade is good for both diplo and cash, so freighters early on is good (you won't have military ability right from the start anyway)
- you need lots of constructors; one is sacrificed to make a starbase, and another is used up for every starbase module (upgrade).
- I didn't beeline the tech line, but worked on it whenever there was nothing pressing, eventually making it to the omega research centre.
- Starting to beeline the cultural conquest line now, to win that way.