To correct lens and camera issues, you can add a traditional "S-curve" to the Curves of the photo, then slightly increase the saturation of the photo, then set the Levels using the "Auto" setting. That should correct any problems...
Auto works quite well most of the time, unless you are going for a specific look (but if you are going for a specific look, you probably already know exactly what you were trying to adjust anyway, and could do it more directly).