Usually, i like to create the music first then the sound effects. But this time it was the other way around.
Archenemy sent a list to me with his ideas, he described the sounds that were needed to cover all parts of the game.
I must say, his ideas were great, gave me a clear direction so my job was easy :)
All i needed was some cool bleeps and bloops with swoosh and kabooms. Well, that was almost all.
I was searching on the internet for computer noises, bleeps, electronic zapps, etc, etc. After i've collected a lot of wav's i started to create my own stuff.
A bad sounding deep noise could work well with a high frequency computer beep, sometimes this is the trick.
Layering multiple sounds, using eq to separate frequencies and pitch shifting is easy to create unique but high-tech noises.
The sounds must be cool, they have to match their function. Eg. a menu click must be simple and if it annoys the player after ~30 clicks then it is a bad sound. If a fleet moving sfx can be recognized as racing cars then the sound effects is bad, bad, bad!
Important sounds should be louder while we can keep the others quieter, the overall balance should match the music loudness.
Oh, and don't forget the fact that sound and music need to be approximately on the same tone, otherwise they will be disharmonic and might be annoying to the player.
I was lucky because it was easy to pitch the musical sounding effects to the music base note and they still sounds good :)
After HomeGnome implemented all the sounds to the game i was surprised, only the fleet moving sound was annoying and a bit too long for the visual effect.
And now, i'd like to share a screenshot of a layered sound (colonize sfx), made in Adobe Audition: