I did some research on this as my cabin looks like a claustrophobic brown cave. You can find ideas if you google things like 'yacht interiors'. You'll find pictures of high-end boat salons designed by experts.
There are also lots of websites that offer generic advice on picking colors/patterns. Patterns, stripes, plaids all tend to bring things closer, as do dark or strong colors. A lighter solid color, or fine pattern that reads from a distance like one color, tends to open the space up visually and make it seem larger, assuming that's what you want. Lighter colors reflect more light, so the cabin is likely to be noticeably better-lit. Whites get dirty easily but there are lighter colors that are less likely to have that problem.
I want to find a way to cover the teak walls with something light-colored but that can be stripped off in the future without harming the teak.
Meantime, I gave up and got a new voltage regulator instead.