DIY Project: How to Recover a Seat Cushion

I have two close friends, both thirtysomething, who seriously don't know their left from their right. It's kind of amusing sitting in the passenger seat as one of them, Laura, constantly inquires, "Do I make a Laura or a Brian at the stop sign?" Situations like this make me realize that what's common sense to some is often incomprehensible to others.

Another example: recovering a simple seat cushion. When a super-smartypants friend recently asked me for a quote to have his barstool cushions recovered, I thought he was kidding, assuming he'd just whip out the staple gun and update 'em himself. But why should I think that? He doesn't do this stuff everyday; I do. So for any of you wondering what to do about cool chairs with not-so-cool cushions, here's the rundown on how to update them yourself.

P.S.: At 34, I still have no idea how the hell to tie a necktie.