I was always a straight A student until the 6th grade. It took me so long trying to figure out what was going wrong, but i did a few things to help myself.
1. I know this will absolutely SUCK, but try and do an online free course, such as kahn academy. Kahn academy is my favorite because there are tons of subject and all different grades. Try to do this as much as possible.
2. This may not apply to you, but I have an extremely smart brother, so I got him to help me.
3. Try to turn in your assignments before the due dates. Stay on top of your assignments and discipline yourself.
4. Sometimes teachers aren’t understanding, but you can try to ask them for extra work sheets that don’t go into the grade book. I did this and caught up on tons of things.
Hope this helped and have a great New Years!