good one is to disable xinetd (-nolisten TCP option)in the etc X11 xdm xservers script,also use your host deny/allow to set up ports eg webmin to recieve local connections only eg. in hosts deny,
ALL:TELNETD
ALL:WEBMIN PORT that you use if using webmin then go to hosts allow ALL:LOCAL also check running process shut down anything you dont need also set up a firewall webmin is very handy for these two things.