Check time on DC and workstation is within 5mins 😉
One additional thing I found very handy was the ability to join the domain using a specific server. The best way I found to do this in our situation was with powershell. All systems were Windows 7.
Type add-computer -?
Specifically: “add-computer -DomainName gwlab.net -Credentials washburng -Server gwlab.net\DC2″
Tons of other options I recommend considering but this for sure makes pointing to a specific DC a breeze.