Look for inspiration in other items that relate to the them. When working on my current bucket, I looked at what type of weapon, vehicle, how technical, what time period, all those aspects for inspiration.
Found a few pics of cars and thought, IF #DarthFettious (working title) drive a car, that would be it. That settled the paint scheme. Yes, it resorted in gloss black, flat black, red highlight, silver/metal base but in a combination I'm yet to see.
Sometimes the inspiration can be from something completely unrelated.