How to thoroughly clean a fish tank that my goldfish died in? :(?

Hi there, was wondering if anyone out there knows how to clean out/ disinfect a standard size (11 gal.) used fish tank. My goldfish just died in it sadly, and I want to be able to use it again for another fish soon. I'm thinking the goldfish died from natural causes, but would still like to use caution, and do not want to give my new fish any diseases. Thank you so much!