This page collects ideas about what it means to be a good sheriff. This provides more background and motivation for why you're sheriffing and what you should do.
The sheriff's number one job is to respond to tree closures and communicate what is going on, not to fix the problems. (Job #2: public safety: re-open the tree when it's safe to do so.) Quickly updating the tree status and then tracking down owners for issues is much better than silently poring over logs for 15 minutes while other people are probably doing the same thing. You're the mutex, not the main thread. Signal early, signal often.
Please put your day job on hold for two days and focus on the commons. (You're only asked to do this once or twice a quarter.) In fact, instead of passing the quiet time by trying to do your day job, you should be thinking about making sheriffing easier or fixing flaky tests. Your time is already blocked off for sheriffing, so it's OK to dedicate that time to the commons.
Drop out of all meetings during your shift. People can deal with your absence from a meeting when you're sick or on vacation. When you're sheriff, they should pause the meeting for a moment of silence to thank you for watching the tree while they're meeting :).
Yes, you can take a break. Everyone has to go to lunch. It's conceivable that a sheriff might benefit from not looking at the waterfall for 10 minutes while she makes herself a coffee (or eliminates the previous coffee). Just see point #1: communicate that you're going to be offline/AFK and for how long. If you're lucky enough to have a co-sheriff, arrange for coverage. Update the tree status/IRC channel when you go home for the day so everyone knows that sheriffing is back in the public domain.
Moreover, the IRC channels are full of people who can help when you're out of your depth.
Channels: #chromium or #chromium-os.
If you can't be a good, full-time sheriff during your shift, arrange for a swap. If your job requires lots of meetings and interruptions, stay off the sheriff rotation: you might think you're being a good citizen, but if you really can't dedicate yourself to the shift full-time, you're actually hurting the team.
Conversely, if you're new to this and don't think you can do a good job... don't sweat it as long as you want to help the team. See points 1 and 3: communicate and ask for help on IRC and you'll not only be helping the team, but you'll be learning and gaining confidence to be even better next time.
Also, we don't need martyrs. If you're on the rotation for WebKit gardening, you don't need to be on the Chromium rotation (and the memory rotation and the Chromium OS rotation). If you're so awesome that you can be on multiple rotations, join the troopers rotation and become the escalation point for mere mortal sheriffs. (Contact a trooper for details - if you don't know any, you can find the currently scheduled one here.)
Whether you're a first-timer or an old hand, letting the team know about the problems you had during your shift helps. Most of the time, these problems are issues we need to address as a team but we can't take action until someone brings them up. Sheriffing is not penance and there's no need to suffer in silence. If there are flaky bots that plagued you or missing documentation or anything you didn't feel prepared to handle, you're probably not alone.
Send email to chromium-dev or chromiumos-dev after your shift to document the shi(f)t that happened to you. It will help the next sheriff and it might just help the rest of the team understand common patterns that need to be addressed.
If you have theses to add, please do so. Keeping the trees green is a community effort and depends on people sharing their knowledge.