I receive assistance from the aliens, of course.
No, seriously, do you mean for XOTM (Game or Conquest of the Month) competitions or for a game you start up? If you can select your settings (landform, water type, number of opponents), and find a good map, then you can make it easier to get a faster finish and play accordingly. In XOTM competitions, you might have to do some things to win that you wouldn't want to do on a more fast research friendly map (like deal with raging barbarians on a high level). There's some good advice over at the HoF (Hall of Fame) threads for non-XOTM maps, and for an XOTM type map, I'd just check those threads. We have a spaceship game going on in the current gauntlet competition for the HoF, so you might want to pay attention there. We also played a diplomatic game last month, and many of the strategies come out as similarly. If you want your fastest spaceship victory and don't care about difficulty level, this seminal
thread will help you get started. Tone has good advice in general for almost any type of game... except you probably won't need barracks on Chieftain or possibly other lower levels.
Optional said:
It helps being at a high level, where the AI will research quicker.
Do the higher level XOTM games have faster spaceship finish dates than lower level ones? I haven't checked myself. For HoF type games, it actually does NOT help to play at a high level for a faster launch. It helps to play at a lower level, because of several reasons including, but not limited to:
1. Cheaper tech costs
2. Less of a need to build military
3. More land easily settled (it's cheaper to settle than conquer)
4. More content citizens
5. Luxuries more easily settled
6. Wonders more easily built
7. SGLs more readily had
8. Less corruption which implies the luxury slider producing happiness easier, and more cities that can build things easier.
If you play at a higher level, where the AIs can do research, then trading techs intelligently and helping the AI out will certainly make things go faster, as Archphoenix's small Deity SS game very well proved. At lower levels gifting them a luxury or two might make so they have a little more gpt for sale.