A good place to start would be the Accidental DBA guide (link in my signature), good book on some of the common problems faced.

The stairways section of the site as well has good topics starting from basic overviews to in depth detail as the stairway progresses etc.

Obivously nothing is better than experience. I would suggest purchasing a copy of the developer edition of SQL, usually around $50, it has all the same features as the Enterprise edition does but you cant use it in a production environment, and just play with it.

There are plenty of good books out on the internet about various topics, but would ultimatly come down to the path you want to take, will it be more development DBA work, support / production DBA work or business intelligence work.