1. Learning to say no is said to spare you from stress, because you shouldn’t be pressured into doing something you don’t want to do, saying no will save you a lot of time and trouble.
2. Firstly you shouldn’t alter yourself if it’s not what you want, but if it is then start with something simple, getting a schedule, and writing your to do-list, and trying to let go of bad habits, or example procrastination, if the problem is lack of motivation then get rid of anything that makes you unmotivated or distracts you like a phone, and start replacing your usual ways of wasting time by useful ones like educational games, or making flash cards, this’ll help motivate you... etc