James Savidge works in Cincom support, and he's talking about ways to make your life easier when you need to debug problems that crop up. The first thing he did was a gentle - and funny - request for people to Read the Fine Manual :)
First tip: Remember the file browser, which can give you a quick view of either bytes or formatted source (depending on what you're looking at) of files. Next, he's going through the profiler (and the multi-allocation profiler), which a lot of people forget. I can attest to that - I don't know how many times I've been helping someone track a problem, and had them be surprised when I pulled out the profiler.
There's also the Memory Monitor (contributed), which can help quite a bit. It includes extensive logging facilities. Back when I was at Cincom, I covered this next bit pretty deeply in my screencasts - the various kinds of probes you can insert for information or debugging using the debugger.
Now a newer tool that I'm not familiar with - the benchmarking tool, which originated in ObjectStudio, but now also works in VW. Since it's a UI driven tool, it won't work headless.
Next, he's going over a tool that I've found to be very helpful - the logging for the various network protocols. When you don't know why your protocol requests are failing, this will let you see the traffic exchanges in detail.
As basic as it sounds, don't forget the Transcript (or the new #out message, which came from ObjectStudio). It's highly useful in server apps, because you'll typically toss the Transcript to a file. I've used that a lot.
Need to watch message sends - the Spy Tool (VW and OS) does that. It does not work in Web Velocity yet.
This next bit is something a lot of people are unaware of - command line options for the VM and image.
James is recommending my screencasts (the ones I did at Cincom). Those are still quite useful, but they aren't being updated now - so as time goes by and new releases of the Cincom products go out, they'll get more and more dated.