If you read Lifehacker, chances are you've been designated as your family's de facto IT person, and you've probably spent more than your fair share of hours troubleshooting applications you know no better than the person asking. How do you do it?!
(Click the image for a closer look.)
Popular webcomic xkcd hits the nail on the head with 90 percent of the troubleshooting most of us end up doing with this spot-on Tech Support Cheat Sheet. The only thing missing is the "If you haven't already, restart your computer and try again" entry, though that's probably more fitting for a "Why won't my computer do X?" rather than "How can I do X on my computer?" flowchart. The chart's a little on the passive-aggressive, Let Me Google that For You side, but it's also a fairly accurate guide.
Tech Support Cheat Sheet [xkcd]