In addition to what has already been suggested, I can advise you: OWL (online writing lab) at Purdue University - free online resources for writers of all ages, including grammar and mechanics tutorials. The Great Courses Plus -offers a course specifically for SAT writing preparation, focusing on developing the skills needed to succeed in the SAT writing section. Khan Academy - free courses on writing, including grammar and mechanics, writing essays, and college admissions essays. You also can try to find freelance writing coaches/editors.

Haven't heard of them before but it looks great! I love this learning idea.

I can reccomend Practice Java by Building Projects (Udemy Course). For Basic/Beginner level, projects are very good.