Does anyone have good tips for working with White?

[toxic atlas]

I'm painting some Dropzone Commander and saw that attatched paint scheme in the book, and like the high-gloss Stormtrooper-y kinda look. I know painting with White is always a challenge, but I've started trying to pin-wash some of those details, and cleaning up the stains afterwards is just... hellish. White paint covering up a black wash, I know, I know, I brought this on myself, but still. Does anyone have a tip or two?

[trail lodge]

Work with off-white rather than pure white as not only does it cover better, it also means you can then highlight up to pure white if you need to. Other than that, yeah lots of smooth layers and patience I'm afraid