If you are behind a router, you don't need to do anything, just don't forward the port. If not, then configure your firewall to only let Remote Desktop connections through from computer on the local subnet. The port number is 3389 if you need to know.
None.
Nah, I saw the port, okay, so that works, thanks.
None.
Just a warning about Remote Desktop Conection:
When other users get a hold of RDC, you may find you need to limit the users who have access to a computer from another.
Most oof the time, you can configure RDC Client and RDC Setup to prevent users, by asking them for double authentication ( asking for a password before RCD'll connect to the PC).
None.