I’m a therapist with ADHD inattentive type. Most colleges have a handicapped department that can help with accommodations that have been described above.
In my own case, before I was ever diagnosed, I found that sitting on the front row and asking questions helped in maintaining my attention.
I once had a wristwatch with lots of buttons on it, and using that I discovered that at exactly 4 minutes my eyes would be going over lines in a book, while I was thinking of something else. The watch would beep and I would return to my reading. You might be able to find one at radio shack.
If you are hyperactive, it might help to take a soft rubber ball to class and squeeze on it at the same time you are writing. That might dissipate some of the energy and help you to concentrate.
E. E. Douglas, M.Ed. LPC LMFT
P.S. In college you do most of your work out of class. Nobody pesters you to do better, and whatever grade you make is not something the prof. worries about. You attend class 3 days a week (usually) and it looks like you have lots of free time (Not.) Everything is a distraction. Your friends want to go somewhere, somebody is playing cards, somebody wants to come in and shoot the breeze, there’s something on TV, etc. There is noise in the hallway, you want to go out with your girl, and so on. Watch out for the distractions. They’ll affect you more than the average guy. Watch out for procrastination. It’s seductive, and you’ll seem to have plenty of time, until you don’t.
Notice that a lot of your friends who seem to have lots of time first semester aren’t there second semester. Notice that if you’ve studied well for a test and ace it, if the prof puts a distribution of grades on the board, there are lots of C’s and some D’s and F’s. Those are the ones who seemed to have a lot of free time to fool around.