One thing I found helpful was to start fresh. I marked everything as read and then only looked at new posts unless I was searching for something specific.
I look at the dates down the right hand column and keep track of my last visit. Anything after that date, I click into and then look at whatever is marked as new, but as a moderator I'm looking at the whole board. You don't have to do that. You can pick sections and topics you want to follow. This is an especially good idea while you get the hang of it. Take it one area of interest at a time.