[SamuraiProgrammer]

One tactic I have seen used / abused works like this:

Choose Ancient Race.

Claim the entire Galaxy.

Trade your claim of empty systems that you will never use because they are far, far away to naive computer races for home planets.

Watch your score climb like a rocket.

Make trade-savvy races surrender because your score is so much higher than theirs.

Enjoy unbeatable advantage over other human players.

This tactic is so unbalancing, we have actually outlawed ancient races and surrender in some of our games.

This is only a problem because the computer players were willing to make these ridiculous trades. Oh well, you can't have everything.