Are you talking just little annoying breakouts that wouldn't matter if you weren't having your picture taken, or time to pull out the big guns and kill the zits dead because they're ruining your life breakouts? Oh, and you might want to ask on the acne board, but that's more for serious acne suffering, not just the rare blemish.
Okay, lets try the basics. Forget proactive and all that over-priced stuff you see on TV and such. You can pretty much copy it with a trip to Walgreens or even just the grocery store. I'd suggest the Clean & Clear line - can find it anywhere and fairly cheap.
First, ditch your facewash if it has any dye, oil, or overkill smelly stuff. If you wash your face a lot, I'd suggest the Oil of Olay sensitive skin face wash stuff. I use it and adore it. And then you know you aren't being irritated because of your soap! (Oh, and Head & Shoulders is a good shampoo if you think your current one might be breaking you out, and it will kill most any shoulder, chest, or back pimples.)
Now for the real pimple fighting! Grab two Clean & Clear face washes, one with BP and one with SA (if you don't know what those are, you've never faced a pimple before - but just ask and I'll fill ya in). Use one in the morning and one at night. But start off slow, like every other day. This is why having a non-medicated cleanser is nice also, so you can switch to it if you start getting dried out.
Just that alone can hold off the small stuff. But if you need to feel like you're really doing something, get a spot treatment also. BP can sometimes irritate or dry you out (don't get any of the 10% stuff, 2 and 5 works just as well in my opinion). So use with caution until you know how you react to it! SA is the safer way to go for most people, but not as powerful. Although this is better for blackhead fighting. You can use it on your nose without becoming Rudolf. And finally there's good old hydrocortisone. It's not labeled as an acne product, so you'll need to leave the Clean & Clear section to find it, but it helps! Bye-bye redness and itch! I suggest using it in addition to either SA or BP spot treatments. But don't rub it all over your face, just put it on the pimple. Same goes for everything. Do overdo it! You could cause a rash or make things worse. So step away from the mirror, and wait it out.
But now you should be set. Though you might want to grab a good make-up for picture day. Good luck!