There are four ways to win:
Cultural victory - which you research tecs and build items on your planents like embassies, cultural exchange centers and wonders that increase your culture. Essentially, you can see how you are doing by clicking the cultural button, which is next to your ship button on the mini map.
Alliance victory - This one is sort of ambiguous in the sense that the other players have to like you and possess the tech to actually enter into an alliance with you. Having the diplomatic translators trade item does help but doesn't gaurentee that they will want to be your friend. Of course, then you have to put up with going to war when someone else goes to war with your new ally.
Technology victory - This one you just have to research every last tech on the tree until you get to "Beyond Human" Once you get this tech researched you have about say 2 to 4 turns before the game is over. The cut scene is pretty cool. Your culture becomes this electrified white opaque entity.
Military Victory - Just wipe the map clean of everyone that has a planent. This cut scene for this is interesting too. The excited yet reserved lieutenant comes up to you and says to a pensive commander looking out the window overshadowing the obit of the home planet "I've just gotten word from the front sir.They're gone!, They're all gone!"
As far as ways to win - pick your poison.
Some thoughts:
Here are some things I've gleened from the intelligent and cunning players who grace these boards.
In the beginning of a game location is key. Create colony ships as fast as possilbe. I took this individual's advice and made my tax slider has high as possible until the morale rating was around 85 to 90%. And then moved the production slider to 100%. Now this gives you a negative credit, but that's okay. It will increase your planet and tech output. Set the ship and tech bars to 50% each and the social to 0. This will help you make ships in about 5 to 6 turns depending on the planet size you have and research techs in about 4 to 6. Colonize to planets the furthest away before you colonize to planets in the system. You start with one survey ship and colony ship. Use the survey ship to locate new planets and find goodies along the way. Unfortunately at 2 square a turn will take some time. Asteroids are always good to find free non produced ships to help locate and uncover space. The planets are unmarked but you have to know whats there first. Get a survey ship quickly. At about 3 to 6 turns you need that extra move to find planets and resources. They move at 3. I always research to get the Gravity Accelerator trade item. This make a scout from 3 to 5, a survey from 2 to 4 and constructors form 1 to 3. This is a huge difference compared to the AI. Once I have this available to me, I set the social to 20% and usually keep it there for a good part of the game. Then pick the biggest planet by production and quick buy the item. This ends up giving me a -450 credit. Now set everything so that you have a positive cash flow and work you way back to positive. This trade item adds 2 to your movement, which may not seem like much but he who arrives first gets the spoils. This philosophy is based on the idea that knowing where planets and resources are help you get there faster and first before the AI has a clue. Each planet and resource adds to you travel area. Planets add around 3 sectors to your travel radius and I think resources add about 1 or 2. Someone can clarify for me. It is also to your advantage that you have a decent start board. One time I had 5 yellow stars in the same area and 6 more is the outlying sectors. Earth was a 19 and sol a 15. Every planet was making colony ships and scouts.
When you know where your resources are, determine where you trade routes are. Naturally you need a trade partner. Pick the highest quality planets, either one by itself or multiple in a sector. I had a 33, 33 planet system trading to a 20,18 minor race with a research diamond along the way. Sent constructors to it and made some good cash.
Every ship for defense takes from your cash. The better defense the more it costs to maintain. Given. Depending on where the AI is, minimize the defenses on planets to help boost cash. Obviously, those planet systems that are of most value should get defense regardless, but that's a personal call.
Since the 1.04 version, the computer gets a serious jump on most things, especially population which drives the economics of planets and production. You will catch up eventually. It took me some time but since I had way more planets and resources, I passed them up.
Hope this helps a bit. The boards are great for knowledge and check out the GC bible on the link. Later