I would like to change total document background colour; for example to Yellow: I have used two packages:
\usepackage{colour}
\usepackage{xcolour}
But I am unable to get my output, is there any solution?
The pagecolor package adds some page colour checking options to that provided by xcolor itself, which may not be necessary:

\documentclass{article}
\usepackage{pagecolor,lipsum}% http://ctan.org/pkg/{pagecolor,lipsum}
\begin{document}
\pagecolor{yellow!30!orange}
\lipsum
\end{document}
It automatically loads xcolor if it's not loaded by default.
There is no package colour but it should be color. Similarly xcolour is xcolor. BTW, you can use \pagecolor{yellow!30} to make pages yellow.
\documentclass{article}
\usepackage{xcolor}
\usepackage{blindtext} %% to add dummy text
\begin{document}
\pagecolor{yellow!30}
\blinddocument
\end{document}
For adding more fancy coloring this answer may be a starting point.
colourorxcolourpackage. To the dismay of British TeX users, the American spelling is used in the names. – egreg Nov 13 '12 at 00:12