Presumably, your brain as well (but that's only an assumption).
Step1
FIRST: You cannot. Killing time is a metaphor. You just can't do it. So give that up, if you can. Read TAO TE CHING, available online, for lifelong assistance with this part of the "process," as "they" say.
Step2
SECOND: Never leave home without a book (and your glasses, if you need them).
Step3
THIRD: Patience. You're around other people most of the time, and they are as "bored" or "frustrated" as you are. You're a member of the club, but you're better equipped than are they. Somebody "in front" of you pulling out her wallet only AFTER the groceries are rung up, then struggling to find a pen, and then slowly writing a check that might not be approved? It's their problem; not yours.
Step4
FOURTH: Think of time not as a conduit, a kind of "tunnel," but rather as something that you're aware of mentally, constantly. It's your friend. Hey, at least you "HAVE" time! (The dead do not.) Keys not rightly configured on your key chain? Stuff to clean out of your pockets? Does your wallet need re-organizing? Deal with it now.
Step5
FIFTH: Dream away. Your mind sets the limits here. Fantasize. Notice what you are thinking. I recall jogging for 30 minutes and suddenly realizing that I was pondering my finances, but in a real sense, I was unaware that this is what I was doing. As soon as I realized I was doing that, and had control over my own mind, I stopped and started looking at what was all around me. A great tonic. You don't need a zoo to be fascinated if you are aware. As Allen Ginsberg once said, "Notice what you are thinking."
Step6
If all else fails, you've got your book. I recommend Plato's REPUBLIC. You can read two lines of it and think about it for the next fifty years. It's "deep," and it's certainly not boring.
Tips & Warnings
Some cultures conceive of time as a circle.
Request information regarding Nietzsche's view of time.
Remember that "bored" is your least favorite adjective. Life (are you KIDDING ME?!) is not boring; only certain people are.