Participate! The Duck is well-known for its welcoming attitude towards newcomers and beginning comic creators.
Look around the site and find some comics you like and want to follow. You can use the "Favorites" system to track them.
There's a lot of information to be found in the Forums (forums help page), Tutorials section, Quackcasts, and other areas of the site. You can post comments all around the site and participate in the forum whether you have your own comic or not, so go ahead and start talking!
You can also make your own comic, and use some of the social networking elements of the site to promote yourself and get readers.