I'm not sure about proper settings for my scene (cycles render). I want to balance time of the rendering and the realism, because render takes very long time (f.e. because of used textures, with every modificatior on - like subdivisions etc - there is 560k verts so in my opinion it isn't that much). I am using the pro lighting skies addon for lighting - "morning03" and "cloudy08". In the first version I used glossy shader imitating water, and on the second I added leaves (objects copied with the help of the particle system and weight paint). These are results my previous renders (scenes differ a bit from themselves - one version is priorer and other one is more detailed). Some scenes don't look that bad, but their render time for sure is.
Cloudy: Default settings with little modifications (render time 3-7h)