Chem is usually the first course that requires the skills of study control and math application. First chemistry studies are really just a math word problem course about chemicals.
The best way is to learn chemistry is to do the following:
1. Take good notes EVERY day.
2. Copy those notes over in another notebook in a good hand EVERY night when you get home, filling holes as needed.
3. Ask the teacher at least one question each day.
4. Read the assignment twice before a class. Once each day for two days is best, if you know in advance.
5. If the teacher assigns the odd problems for homework, do the even ones also. If they assign all of them, ask the teacher where you can get more problems.
6. Start the problems the day they are assigned. You should finish at least a day before due, if possible so you can ask for help.
7. Visit your teacher during office hours each week to get more instruction on topics not clear. Even if you think they are clear, go anyway. Ask the teacher for exceptions or additional harder examples.
8. Go to a bookstore and find the Chemistry problem books and learning guides put out by different companies (SAT prep and the like). Find one on your level and buy it.
9. Go to yard sales or goodwill stores and find one or two textbooks other than yours. Sometimes, ideas click better from different books.
10. Visit your teacher after each test to make sure you understand eveything you missed.
Chemistry is based on problems and learning how to work them, as well as learning the concepts. It is really a math course with chemistry as the subject and you must do repeated problems for it to click.
The problems most students have is not working the problems, thinking it will just come to them, and the biggest, not taking advantage of the teacher. They are there to help and if you want to learn, use them.