Hi, some of you may have seen me popping in and out for the past few months, I keep studying on and off for 270 but it's difficult finding the time

Anyhow, to cut a story short, I don't administrate the domain at work, so I don't really get much experience using and working with Orginizational Units and Group Policies.
My question is how did you all gain your experience\understanding of it? I have a VM lab but I just don't know how to really implement it into experience without a scenario requirement. I obviously understand their purpose and how to use them, I keep getting questions like this pop up, although I don't know such policies exist:
You administer a Windows 2000 network for a company that manufactures and distributes small appliances. Company policy dictates that all user logon events be authenticated by domain controllers. You must ensure that this policy is carried out. All client computers are running Windows XP Professional.
Which of the following should you perform?
Implement a Group Policy Object that requires domain controller authentication before a workstation can be unlocked.
Implement a GPO that prevents anty previous logon events from being cached.
Grant the Full Control permission for the Domain Controllers container in Active Directory to all users.
Apply the Basicwk.inf security template to all client computers.
Not just this question, group polcies and OU's in general.
Any help is appreciated. Thanks