A site that I really like and often refer people to is the Slacker's Bible
, sponsored by Mad Penguin and maintained by a community of Slackware enthusiasts. Maybe take a look at the Common Tasks, System Administration, or Network Communication sections for a start or think of something that you'd like to do with your machine, then research it and do it!
The door's really wide open for you!
edit: ahhh, you beat me to it nazmin!