GREAT critiques, @bensharpeningcharacter!
The best way to keep noise levels low is to keep your ISO setting low. So, ISO 100 is going to be a whole lot cleaner than ISO 800. The best way to keep the ISO low when shooting in low light is to use a tripod and slow shutter speed.
The attachment is a 100% crop on a photo that was taken at dusk, long after the sun had set and it was almost too dark to see anything but the sky. However, it appears very clean because the ISO is 50 and the shutter speed is slow, 30 seconds.
