I've had acne for about 6 years and I am now 23. I've tried many different things. I washed my face a lot, I drank water, I used proactive and tried many other medicines. There are two parts you should consider when getting rid of acne. These are things I did that helped ME (and may help you):
PART ONE
There could be things that are KEEPING your acne from going away. Things such as long oil hair (that's why it is important to wash your hair), dirty towels, not washing your face, popping pimples, not washing your hands and touching your face a lot, wearing hats and not washing them, and not washing your face after exercise. Your lifestyle may also be feeding your acne.
PART TWO
There are things that you could DO to PREVENT acne (this helped me more than part one):
Change or wash your pillow sheets EVERY NIGHT. I don't change them but I wash them at least once every two weeks. Instead of changing them, I bought a bunch of white T-shirts and cover my pillow with them before I went to sleep, then swap out the T-shirt for a clean one the next night. At the end of each week, simple throw all the dirty T-shirts in the washer. This helps because you sleep on your pillow every night and it is important to help your face STAY clean when you sleep. Pillows tend to gather dirt and oil when you sleep on them.
Buy some organic lemons (organic is important because you don't want chemicals from foods on your face, only natural stuff) and apply the lemon juice on your face every other day. Let the juice sit on your face 10-20 minutes, then wash off with cold water and pat dry with a clean soft towel. The acidity will kill bad bacteria and also act like a mini chemical peel for acne scars. The lemon juice will clean your face as well as remove dead skin cells, which is REALLY helpful for scars and dark spots.
Use organic or natural soaps. Many common name brands for soaps and shampoos have chemicals that don't actually clean your hair, but make it smell nice and pretty instead. Brands such as herbal essences, garnier fructis, dove soap, etc mostly contain these chemicals (although they are beginning to change that). This is why it's important to buy organic and/or natural hair and face products.
Before you sleep, apply organic honey on your face. Wash the honey off the next morning. The honey will help bring your natural glow back to your face as well as get rid are dark scars. You will see a difference after a few times doing this. Note: this helps you more for scars than it does acne, but it is still a big difference when you want your scars to go away.
Don't eat too many oily and meaty foods. Fast food is bad, especially fried foods. Instead of eating meat, take protein shakes and eat beans/nuts for your protein intake. Also, try to avoid unnatural sugars, such as candy, soda, and anything that has high fructose corn syrup (you would be surprised at what snacks and foods have this). Make sure you eat plenty of fruits and vegetables (and I mean a lot). Some of the fruits/veggies I eat everyday are: lettuce for salads, cucumbers, small sweet tomatoes, oranges, bananas, kiwis, yellow peppers, apples, lemons (I squeeze the in the water I drink it), carrots, mushrooms, and berries (any of kinda of berry).
And like everyone else is saying, getting rid of acne is a slow process. It takes time for it to completely go away, so don't expect to see quick massive results.