How Do I Obtain The Best Possible Water For My Goldfish's Options

[kinggold]

I know that doing daily water changes and keeping up your filter is a good way to keep your water healthy, but what would be the ideal set up to obtain the best possible water quality.

Filter brands...types...UV sterilizer or not?
what about the filters content?
Any good combinations?(spong filter+canister filter)

Also Any suggestion on prepping the water since I am using city water. Should I be using distilled water?

I have been doing things the way that I have been though to do them and would really appreciate knowledge from others so I can give them the best of the best.

Thank you very much!

Kinggold