1) Download and install Virtual Machine. Any modern virtual machine capable of making snapshots will do, for example VMware. This tutorial assumes Oracle VirtualBox because it's available free of charge.
2) Download Linux Live CD: SLAX and Compiler Pack module for it. We need it to build Linux API headers in native environment. Any other Linux Live CD with development tools will do, but we assume SLAX in this tutorial.
3) Download source code for gcc, binutils and glibc from ftp://ftp.gnu.org/ . You should have determined versions of the software previously. When downloading gcc, it's enough to download gcc-core and gcc-g++ packages only, instead of entire GNU compiler collection.
4) Download source code for libraries gcc depends on: gmp, mpfr and mpc. We will use gmp-5.0.1, mpfr-3.0.1 and mpc-0.9 in this tutorial, but generally latest versions of all of them is what you need. Newer versions of GCC also depend on elf library: libelf-0.8.13.
5) Download source code for Linux kernel. It is required to supply Linux API headers to build glibc from. Ideally, you need to download kernel version reported by "uname -r" in the target system.