oof engineering, that's tough ;_;
1. personally i use google calendars to keep track of due dates/events, and spreadsheets for assignments. it might be a bit redundant but i also have a calendar and a list of tasks hung up by my monitor as a constant reminder lol. my google calendar and phone calendar app are also synced so i don't have to worry about constantly typing stuff in
for actual studying, i find doing practice questions/practice tests most effective as it actually tests my knowledge and reinforces the learning. the feynman technique is also pretty good from my experience
2. i found it really helpful to keep my phone physically away from me when i'm studying. so i set it aside somewhere or keep it on charging. i also make sure to de-clutter my workspace so there's less 'visual stress' i guess? i don't know, but it helps me focus
3. honestly exams and grades lol. but it's also very fulfilling when your hard work pays off :)
but hey i'm still in high school so i'm obviously less experienced and probably less qualified than you to give advice, but hope this helps. take care and good luck!