OGRE is a bit difficult to compile on Windows because of the many libraries it depends on.
Clone the OGRE Dependencies repository. This has the source code of all the OGRE dependent libraries.
Build it using CMake. Make sure you set
CMAKE_INSTALL_PREFIX to a separate subdirectory since this path will be used while building OGRE.
If you get error on
unistd.h, comment that line. I found it could build without using it.
Download the source code of OGRE or clone from its repository.
Build it using CMake. Set the variable OGRE_DEPENDENCIES_DIR to the install path you set while building the dependencies. Set the CMAKE_INSTALL_PREFIX variable to the place where you want the OGRE libraries and executables need to be placed after build.
Pre-built libraries of OGRE for recent Visual Studio versions can be downloaded from here.
Tried with: OGRE 1.8.1, Visual Studio 2013 and Windows 7 x64