ANDY'S ANSWER: The reason that you've started getting pimples in the first place is because your hormones have started producing lots of sebum. Too much sebum can clog your pores and along with dirt, dead skin cells, sweat and bacteria mixed in, there can be inflammation.
Keeping your skin clean is more important than ever, but you also have to be careful not to scrub so much as to irritate or dry out your skin. Washing up, especially after you've been sweating or if you've been exposed to dust is important, as is keeping your hands clean and not touching the places where pimples are likely to come out. Squeezing pimples pushes the bacteria further into your pore, which only makes the area more red and inflamed.
There are over the counter remedies that may help. The most effective ones contain benzoyl peroxide. If your acne becomes extreme, talk to your doctor. There are prescription medications available that are stronger if your doctor thinks you have a severe problem.
Keep hair products off of your skin, and if you need to use a moisturizer, make sure it is one that doesn't clog your pores. Look for "Non-Comodegenic" on the label.
Finally, eating a healthy diet, exercise and getting a good night's sleep are also good for keeping your skin as well as the rest of you healthy.