I'm lost when it comes to diplomacy in this game. I can't figure out how to make most aliens want to ally with me.
What I try to do is on an alien race's stats, maximize the amount of +'s, while minimizing the -'s. Sometimes, especially on higher difficulties, I can NEVER get someone to get above "Friendly".
In my latest game, on "Painful" I even gave the Terrans a PLANET, and they still wouldn't go above friendly.
What are your diplomacy strategies for increasing friendship, with the eventual goal of forming an alliance? (I'm looking for more advanced diplomacy besides just keeping the aliens friendly enough to not attack you)