3) For me, triggers are everywhere. Oftentimes, even the smallest, most random things light me up. :/ For example, if I'm cooking something in my apartment and my food falls on the floor, I light up immediately.
If it's unavoidable triggers like this, than you're best working on meditation and relaxation techniques. That way when something does happen you're less likely to let loose. Also, if you can, when something happens, close your eyes and breathe. I've learned to be a lot less knee jerk about my reactions by just taking a pause.
Exercise will fall into this too, it helps take the edge off, it helps destress and decompress, I know it seems like a far stretch, but it really does one well. My dog has been my #1 asset to my ADHD, despite all of his distractions, why? Because I'll get moving a lot more than I'll use to. 5-6 10 minute walks a day adds up to an hour of keeping active. That + Dedicated long walks and a little bit of play that adds up too. Some days I'll do 6.5 miles without realizing it. I'm not in the best physical shape I've ever been, but I'm definitely in the best health because of this. This has kept me calmer and more level headed in everything. (No I am NOT saying get a dog hah).
The studio space is less than ideal for people with ADHD, too much simultaneous stimulation, and if you can't manage to dedicate a space to just work (or, at the least, where your back is turned and you're visually "sectioned off") then honestly, one of the best things one could do is utilize your school's library. It will be a lot less distracting (and in turn, "comfortable" than home) which will help keep you focused on your work a lot better. Classrooms work too. If there is an empty work space I say just go! You can also try apps which limit your utilization of the internet so you don't end up like me and tabbing to reddit, seeing a post and then spending the next 4 hours coming up with Theories for the next Halo game.
A lot will be just personal reflection, and learning yourself. It won't be quick, and it won't be easy, but utilize forums like this, keep reading, keep learning, and keep writing down your thoughts! Also if your school has counseling services, work close with them! Talk to your professors as well, they tend to be understanding when approached.
I wish you the best of luck!