WATER, WATER, WATER!
Okay, okay, it's not the be all and end all to skin woes but seriously, once I started drinking more and more water my skin was perfect. And by perfect I mean that I wasn't getting frequent whiteheads on my acne-prone areas. It helped to regulate my skin's own moisture balance so I wasn't drying out and then I wasn't making my skin go into over-drive mode and releasing more and more oil, which acts as an over-compensation for its dehydrated state. But seriously, try drinking more water and you'd be pleasantly surprised.
Now beyond that, I would say definitely try and find products that work for you and your skin type -- then stick with it. I suggest if you wear makeup to use a seperate makeup remover (I swear by DERMALOGICA PRE-CLEANSE -- it's an oil that emulsifies when wet and removes every last bit of foundation, powder, mascara, eyeliner, what have you). Then follow that with a nice gentle cleanser that doesn't strip your skin of its moisture but still removes what the makeup remover might've missed. Then follow with a toner (there are ones that are moisturizing, exfoliating, and so on) -- make sure it's alcohol-free though because seriously, as we all know, alcohol is no good on any skin type. Using a toner is optional, some use them and others don't -- I, for one, can't live without it. But it's a personal choice. Then the most important step of them all: moisturize, moisturize, moisturize! Your choice of moisturizer all depends on your personal needs and your skin type. There are so many out there to choose from but I tend to the avoid the ones with oils and pore-clogging ingredients (you can Google this and find out more). Then as supplements to your skincare routine: use a mask suited for your skintype 2-3x a week (frequency depending on your skin type), exfoliate (again product choice and frequency depends on your skin type -- but do not over do it as over exfoliating is more damaging than beneficial). And again, stick with this routine, it takes at least 6-8 weeks for signs of improvment, if you've chosen the right routine, to show.
BIG BIG THING: don't pick at your pimples. Doing so can spread the bacteria which could lead to more pimples sprouting up and can hinder its healing process -- actually prolonging it and therefore leaving you with those dark spots after the pimple eventually goes away.
And if you can afford it, try having a go at a facial at a medical spa. It's such a luxury but at least the same time, beneficial to your skin.