Shaders are not the sole aspect in making a good scene, and definitely not a general purpose solution. There are a lot of steps in creating the proper inputs for the shaders to even do their work.

If you're looking for a "smooth image", you're probably thinking of Anti-Aliasing shaders, try FXAA (http://timothylottes.blogspot.com/2011/03/nvidia-fxaa.html).

Water is a hard thing to get right, check out this tutorial (http://www.riemers.net/eng/Tutorials/XNA/Csharp/Series4/The_water_technique.php).

As far as general purpose lighting check out diffuse lighting(http://rbwhitaker.wikidot.com/diffuse-lighting-shader), specular lighting ( http://rbwhitaker.wikidot.com/specular-lighting-shader). That should get you a half-way decent thing to look at.

Skies generally are just unlit sky-boxes, though there are some cool techniques out there to make them look good.

This is a deep rabbit hole though, and not something you can just get some shaders for. Good luck!