... such as the tiny buttons on control panels?

I was thinking that the best bet would be the paint black and then apply the button paint (dark green, red and gray) afterwards using the point of a toothpick.

That way I don't run the risk of covering it when I paint the rest of the panel black.

Would this work, or is there a better way to apply paint to minute details?

That's the best way to go about it. I recommend that you do them in white first to give the colours some depth. Greens, yellows and reds are very transparent and without a white undercoat, black makes them look very dark.

Thanks for the tip!

I'll put a touch of white on first then.

Thank you both