tehRonskie, I have been in the EXACT same boat as you. When I was 8, I went to a psychiatrist who diagnosed me with ADD/ADHD, but instead of prescribing me medication, he wanted me to use techniques for the disorder. Then, I went back again two years later, and experienced the same thing. Then finally 8 years after that, I went to my family physician who perscribed me medication for it. Essentially up until my senior year of high school, I was completely unable to get above a mid B in any class. Typically from the minute I got home from school and until about 12 midnight, I would be studying. I really wanted those A's, but I simply could not get them no matter how hard I tried. Once I was prescribed medication, that all changed and my studying was finally actually paying off and I was able to get all A's and a B my senior year of high school.
I'm not sure where on the ADD/ADHD scale you lie, but often times using techniques don't work. However, what seemed to work for me technique wise was to put myself in a completely quiet room with no distractions. Of course I would end up being distracted somehow, but I wouldn't be as distracted as I would be otherwise. I'd also suggest getting a program or web app that would let you block certain sites or only let you go to certain sites for a certain amount of time. Music was often a bad idea for me as well. In the most basic terms, our brains are "asleep" and they are trying to wake themselves up. This is why people with ADHD are so fidgety. The brain is using motor movement to try to keep itself activated. Music stimulates activity in the brain a ton, which is why it could hinder our concentration, as we will then focus on the music since it's stimulating our brains more. The last thing that really helped me was to act eccentric and excited about what I was working on, and make myself believe that I liked the material. I probably looked insane, but F that. Doing this, talking everything out loud, and even standing while studying were certainly beneficial for me.
In terms of being in class, just try your best. Move your leg up and down a bit if you have to. Be a nerd and sit in the front row, too. This way, all you see will be the teacher and the board. No one else will be in front of you to distract you. In terms of exams, keep an eye on the time but stay relaxed. Try breathing in for 7 seconds, then holding your breath for 7 seconds, and then exhaling for 10 seconds.
Presence and intensity of the side effects for medication are different for everyone, and there are different medications available too. Don't let the side effects lead you astray, though. Don't be afraid to try one for a bit and then switch to something else if it isn't working out. Honestly, my biggest side effect would be the fact that I am often not hungry. It's not that I am disgusted by food, I'm just not hungry and would rather not eat. I'm aware of this so I eat anyways, and I force myself to eat the right portions of what I need, so it isn't a problem. Another large side effect that I've heard of is mood changes. I know that I become very concentrated and stay rather serious, though I feel happy and calm. When I'm not taking my medication, I'm crazy excitable, I'm happy and I show that I am, and I'm hyper. Everyone experiences these side effects differently, so the best advice I can give is to try it and see how it works for you.