I sometimes find that color can actually make a room seem bigger because it creates variation and definition - suddenly you can see the corners and you can see the place where the ceiling meets the wall and one side will be more clearly shadowed.
White can wash the whole room out so you can't sense where the surfaces begin or end - and thus you can't actually sense if it's small or large and can feel more like a void. (I'm not sure if I'm making any sense, but I've experienced it with many paint jobs).
That said, I would still avoid dark colors. A light yellow, like a nice sunny butter would be lovely. Neutrals are always nice - the ever popular greige could do the trick. Or, what about an accent wall, still in a soft color? That could help draw your attention to a feature in the room, like a couch with art.
Do you have a photo?
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The blue green wall color
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