I hope to be able to give you lots of hints and tips about how you can tweak and configure Salesforce.com in your Company, but do make sure you have a safe testing environment before you dive in!
The best way to do this is by registering for a Developer Org. Click here
Salesforce very generously will give you a FREE version of Salesforce with all the best functionality, for free, for ever, for you to play with.
Add some test data in, and off you go. Install some Appexchange apps, test some code. Best to try things in here rather than your Live environment.