Great question!! There are a lot of ways to improve at studying, it really depends on what particular part of studying you want to improve at! If you're wondering how you can study better for tests, I would suggest taking notes and committing yourself to studying each chapter and/or unit taught throughout the school year!! When studying for tests, it is best to start early. When it comes to studying for a quiz, I recommend really knowing the concepts taught in the chapter and not only that- it is important to understand the concepts and vocabulary in the chapter. If you are wondering how to improve at studying overall, I really recommend using a planner and/or designated notebook for you to write down a task list and note down any assignments, upcoming quizzes, small projects, and tests! It sounds stressful to write it all down at once, but this will actually help you remember tasks and have a visual reference and reminder of how many things you have left to do. Another rule of thumb that I would suggest is scheduling an hour to two hours each session for you to study, so you know that during those specific times you have already decided you would be focused. One more tip- be wary of having your phone around you, consider putting your phone away or on the other side of the room to charge! If you aren't expecting at least a semi-important phone call or text, I recommend the Do Not Disturb feature when at home and studying. I hope this helped, I wish you all the best!!
What are you trying to improve in? Are you struggling in a particular area/subject? Try to learn from your mistakes and your past quizzes, are you making the same mistake? Try asking the teacher for help and attend after school/office hours that the teacher has. Do you have any friends in class that can help you? Try forming a study group. Make a routine for yourself and get in the habit of studying everyday and doing your homework on time. Find a schedule that works for you and see if your grades improve. Make flashcards
Don't give up on yourself! Try your best and ask for help when you need help
KhanAcademy is a great resource and provides learning material for a many subjects, give it a try!
Trying to improve is always a good goal to constantly strive for at all phases in your life. Try to identify if there are specific areas you are trying to improve, and if so you can find TED Talks, community courses through community education or professionals who offer webinars on these topics. If you are generally trying to increase your knowledge and skills, you can still look up areas of interest and find professionals in those areas who have authored books you can check out from your library, have given TED talks you can stream for free, or have websites with webinars or other materials that you can access.
You may also want to read books on the topic or watch videos that specifically addresses the areas you want to improve.
Hope this help.