"I'm a 'new boy' and have produced a woodland landscape in watercolors which needs the mist of early morning. How can I achieve this (especially since there is no unpainted paper left to use)?"
-- Bud S.
If you're not a purest who wants to use only transparent watercolor, I'd use a little white or light gray gouache (or acrylic) to create the mist. Being opaque, the white will show up on top of the watercolor you've already put down. But it needs to be a very thin wash so it doesn't totally obscure what you've painted or look unreal, so experiment first on another sheet of paper before doing it for real.
Alternatively (and again experiment first), lift some of the color off in the mist area so it's lighter. I'd do it either with a damp clean cloth, dabbing it gently onto the paint to lift some of it (experiment with smearing a little too, to give a feeling of blurred detail that looking in mist gives). Be very sure you don't use a cloth with any paint on it or you may accidentally add color to your painting.
Another method would be to dampen the area with clean water and a soft brush, then use a dry, stiff brush to lift a little of the color. See How to Remove Errors in a Watercolor for more on this technique.