Teenagers who have (mostly) clear skin…?

I need your help. Because of my skin, I have really low self-esteem…I'm a 16 year old girl and ever since being 13 years old I've gotten moderate acne. I never have a day where I'm like 'oh no, a pimple' because I have more than a few pimples all of the time. I'm taking perscription pills and I'm taking proper care of my skin – washing face morning and night, oil-free make-up, oil-free moisturiser, etc.

I've figured it's time to change my diet. I eat reasonably well, but I could be eating much better. There's hardly any fruit in my diet, only mainly apples. I eat lots of tuna and chicken, and I'm now eating only wholemeal pasta, and multigrain bread.

I do, however, eat processed foods for school because they are quick and easy, i.e. packets of chips, biscuits, mac&cheese for lunch, etc.

I feel I should eat more organics and fruits, but I don't know where to start, because I prefer quick and simply and affordable food.

Please describe to me your diet and any clear-skin tips you might have. Thank you for your time!