On the main page, I usually start at the top and make my way down, but sometimes I start with the forum containing the least new threads and work my way to the one with the most new threads.
Once inside a forum, I click on the oldest new thread and then navigate to newer new threads by clicking the "Next Topic" link at the bottom of each. When I run out of threads in that forum, I either go back to the index and select another forum or if I remember another forum that has new threads I'll select it directly from the "Hop to" menu.
