Windows 10 Transformation Pack is not only for Windows 7 users. It actually works with all the versions of Windows starting from XP to 8.1. But why would a Windows 8.1 user use the Transformation Pack, when the real thing is just across the corner? In any case, you can begin by downloading the Windows Transformation Pack and installing it on your PC.
As can be seen from the installation screen, some of the features are not available for now really old Windows XP users. You can choose system font, Immersive UI, Cortana (not really Microsoft Cortana, but something similar), Windows Aero, Start Menu and the auto-colorization feature of Aero. After the installation, system goes for a reboot and then you can enjoy your Windows 10 interface. If later you decide to remove this Windows 10 interface, you can simply uninstall the Windows 10 Transformation Pack from the Control Panel.
Windows 10 Transformation Pack can really make you feel the new Windows 10 experience without actually installing Windows 10 (which may require better hardware). But if your PC is running on Windows 8 or 8.1, then it is better to wait for the Windows 10 – it is going to be released only in a few days.
You can download the Windows 10 Transformation Pack from here