We have oak-colored wood paneling in our living room and we want to paint over it. My first question is what do we need to do to it in terms of sanding, priming, etc.?

My second question is how do we go about choosing a shade of "white"? Our living room is big but is a little dark. I want it to look lighter, but still cozy. We have dark wood furniture and a light beige carpet. We could paint the walls white or more of a cream color. Even a light yellow or blue would be ok. I want the feel of the room to be clean but warm. I just don't know how to decide what kind of undertones the paint color should have, or how to go about deciding. Thanks!
We like the look of the painted paneling. We don't want to remove the paneling, cover it, or fill in the seams.