I finished freshman year of highschool with a 1.9 gpa, how high can I raise my gpa by senior year?

Really changing up and structuring your schedule. Obviously your current one isnt working. Go to a library to study, as being in your room will likely lead to binge watching and procrastinating. Your teachers are not stupid. They assign homework based on whats relevant. Do it. Understand the concept first,and then rinse and repeat with homework. I guess this is advice for someone seeking straight A's. At the very least, attempt one question out of a section (especially in math you have question 2a,2b,2c...all regarding the same concept but with different numbers).

If you do enough questions, then you are prepared for anything a test will throw at you

Get all A's

Uhhh, study? You can do it.

You could try studying and doing your homework. Have you considered a tutor?