Is she taking medication and does that seem to help? There are 2 kinds short acting and long acting. My daughter and I take short acting while my son takes long acting. Short acting is very helpful in getting my daughter to be able to focus and complete her Math homework without too much frustration. The only problem is you have to take it multiple times a day. Which teens might not what to do or remember to do. At home use a timer and a screen time parent app to be able to shut-off access to parts of her phone after a certain time at night and/or she used up all of her allocated minutes which can be set for individual apps. Like she can only be Instagram for 1 hour a day. Let her take a break when she gets home before homework. Work on making homework schedules and plans. Model for her how to break up bigger projects. What you need to do is scaffold the skills she needs to learn. With you or her teacher teaching the routine and then slowly releasing the help given and transferring the responsibility in small pieces so she can feel successful with each step before she has to do all of it.
At school ask for extra time on tests and projects, written study guides, directions to be given in oral and written form. If she can have a study skills class/guided study hall. Extra set of textbooks to keep at home.
Ask her to brainstorm or list all the things she is good at and the things that are hard at school. Then ask her if she could think of any things that would make school easier. Is there a specific class that is hard or is it remembering to turn in assignments? Are they electronic assignments in Google classroom or paper assignments? How does she organize her notes? In a notebook where pages won't fall out or a binder? What if she uses tape and just a notebook so she can keep everything for that class in one place. Maybe even a 3 subject notebook. Then get a LARGE 3 inch binder that can fit loose leaf paper, hard plastic folders, and her notebooks. For her 4 or 5 main academic classes they should be 2 subject notebooks and electives can be 1 subject notebooks.
She also needs to learn how to use a paper planner and her online calendar on her phone.
If there are specific times she needs to do things then she can set alarms on her phone to remind her.
