How to study efficiently with ADHD?

I'm 25yrs old with ADHD in college. I graduated from high school in 2006 with honors without ever having to study because I always "just got it." Even now I'm about 30 days away from completing my freshman year of college with a 3.8 GPA and still haven't obtained any study skills. Typically before a test I'd take my meds (adderal), look at the material for the 1st time and cram or basically rewrite the PowerPoint slides for 2 or 3 hours (not realizing how much time had gone by) right before the test, and then do a brain dump on the test which typically yields me with an A or a B. However being as smart as I'm, I can recognize when I need to apply myself. I have an upcoming test that I'm COMPLETELY OVERWHELMED by, so much so that I've been afraid to even attempt to tackle it, so I've been doing the easy, peasy, requires little effort stuff instead. The issue is I'm not sure how to adequately study to retain the info until wed. I know a 2-3 hr session won't suffice. Sometimes when I take my meds I focus too hard and spend an hour and a half on chapter 3 when the test will cover 3, 4, 5, 8, & 9. Also since I'm not sure how to actually "apply" myself and because I'm fearful of how much I have to tackle, I end up playing games on my iPhone, watching Netflix, sleeping, or doing an easier subject. I'm sure not the only college kid actually suffering from ADHD, so any advice is appreciated!

A lot of people that have ADHD do this very simple diet- avoid sugar in any form (except for fresh fruit), avoid MSG, food dies especially red 40, and all kind of fast food (I realize that is difficult when you are in college, but try). All those things have been proven to be bad for people with ADHD.
Try yoga, a lot of people thinks that helps, it will teach you to breath and that can help you to concentrate. And when you feel overwhelmed, do some kind of cardio work out, like running, biking and go outside, it will help you too to concentrate when you get back to your books. Just 15 minutes will make a big difference.

I have seen this help a lot of people, and me too, I don't think I have ADHD, but I get very easily distracted, and I do the running and then I can think much clearer.

There are some great foods that help immensely with concentration. Here's a link that shares some more information about these foods.