My tip would be to install DNS and ensure that it is running properly BEFORE attempting to promote to a DC. Always ensure that your DC uses a static IP, i prefer to use the start of the IP range. Always point the DC to use the DNS server, i always prefer to have it on the same server, as it's primary DNS server then set up your DNS server to forward requests to another DNS server, internal or external, if required. Not so important with 2003 but ensure you have a good naming structure for you AD forest. Ensure you have all OU's etc named and ready to go when you install AD. Finally DOCUMENT everything. This is especially handy if you have a disaster scenario, seen it happen many a time, and will allow you to trace your steps and rebuild to the same standard as before. Take plenty of screen shots as well. As klasika says always take a backup image of the drive for ease of roll back.