The key thing is to check whether the fine specifies a particular traffic code provision that you allegedly violated. If it just says something vague like "parking in an unauthorized location," and the markings really aren't visible, that's already grounds for appeal.
Along with photos from where your car was parked, request through the government services portal or in person (this is important) documentation about the current state of the markings in that area - the road surface plan, the date of the last time it was marked, inspection reports. If the documents show that the markings were last applied a year and a half ago and they're completely worn away, that works in your favor. Judges pay attention to this: the administration is responsible for maintaining the markings, not the driver for guessing where they are.