www.rpmseek.com (for getting fresh .rpm based software)
Reading the OS documentation.
Using the online updater (via mandrake Control Center) to get ALL program updates- final versions of Mandrake are sort-of-betas...
Understanding the intricacies of "dependencies"- so you would be able to install packages without probz. Or else you could install kpackage (included in the 9.1 distro) and try installing software using debian packages (.deb) without having to know anything of the apt-get or apt-install funny stuff.
.deb packages may look funny, but they don't have most of the RedHat (.rpm) packages problems.
And finally (cause it's absolutely necessary) learning to use the shell/console, and a filemanager better than Konqueror or Galeon -also included in the package- it's called Midnight Commander, and it's the Linux swiss knife.
Finally, having patience and will to learn... once figured out, Linux delivers.