There are many things that you can do to help yourself and your learning.
First of all you need a good place to study. A place you are comfortable in. A quiet place. A place without interruptions. A place supplied with the resources you need for study and homework.
Second you need a regular schedule so you can always set down and be able to study without interruption.
You need to make it a priority. Should you have competiting demands, you need to be assured of your priorities and why the work required will in the long run be more fulfilling to your life than immediate temporary interrupts.
You need support. You need people who can help you with questions. You need people who give you good feed back. You need people who like to see you well and let you know it.
You need people's encouragement and approval.
Don't always look at homework as a chore. Try to discover what it is in a subject that makes it worth studying. What makes it interesting. How it may empower you. How it could end up contributing to your life. There's always a reason that a subject became a course of study.
Take care of yourself. Eat well. Exercise. Feel Good. Be physically healthy, be mentally health, be spiritually healthy, follow your conscious. Feel well. Do well. Go into a test taking stituation, well rested, properly feed, balanced, confident with a clear head, well prepared.
Learn to read well. There are many reading stradegies. Preview what you will read. See what segments the subject is divided into. Look at the subject headings, the figures, tables, maps, photographs, diagrams, charts. This will help you keep organized. Then when you study the details, it will make sense how they fit into the larger scheme of things.
Take a look how the study materials are organized. Do they have special symbols that indicate 'notes, 'tips', 'hints', 'recommendations', 'cautions', etc. Do they make use of different formatting styles to indicate 'code', 'titles', 'variables', special glossary words.
Make use of the Table of Contents. It gives you a great way to keep your perspective as to where the particulars you are studying contribute to the larger subject. It also gives you a great way to find relative information that be a big help in learning your current focus of study material.
Make use of footnotes, and endnotes, and bibliography.
Make use of index as quick way to find relative information when you run into a question. Make use of the glossary as well when you run into new vocabulary words.
Take a course to increase reading speed if one is offered. If no course is offered, ask your English teacher for help. They will be very impressed and very willing to help you. Increased speed in reading will let you get your homework done quicker, will make it easier to do extra work, will make recreational reading more fun. It will also help increase your comprehension, allowing you higher text scoring.
Obtain keyboard training sooner than later. When you learn to keyboard well, you also gain a great deal of creative writing ability. This will let you make great presentations, Help you organize your thoughts, write well, make great compositions. Your expressive ability will grow. It will take less time and effort to complete school projects. You'll be able to do more with less effort. It's great. Many of the things you learn in English class will start to take on new life.
If you have some weaknesses in Math, go back and re-work those weaknesses. Much of math tends to be accumalative and each new round of learning builds on previous Math skills. So even if Alebra may take some extra effort, it is worth expending the effort, because it will be a skill you need in Trignometry and Physics and Chemistry and Engineering Subjects and Electricty, etc.
Writing three random lines from a magazine, three times each, is a simple exercise if you want to improve handwriting.
Sit in a comfortable position and with each pass try to improve the shaping of your letters.
Good vision is imperative. Make sure you have a good lens perscription if you require glasses.
Surround yourself with good friends that will help you with your goals.