Since I am also retaking my chemistry classes, I will tell you what I will do to make myself more efficient. I am planning to start from the very basics, periodic table, ionic bonding and basic redox reactions. I will quiz myself on some practice exams and do them until I get a satisfactory score. Then, move onto IUPAC naming and rules regarding it, sure it may sound boring but you need to make sure you don't make previous mistakes. Then, some basic haloalkane synthesis procedures followed by whatever you still need to do.