Before you go into a panic attack just remember that a journal is a great way to keep track of what you are writing, and an awesome way to organize your ideas. Before you start, ask your teacher the reason behind having the journal in the first place. Most of the time a teacher does have a game plan–whether it be a longer essay, a scientific experiment ( if it is a scientific journal), or a specific methodology they want you to learn.
To understand journal writing better it's necessary to explain that how you write in a journal varies with the subject matter.
I will explain a few journal writing techniques for each type of journal:
These are journals you are given for experiments, recording science projects and monitoring progress. Usually this is done in Biology, Chemistry and Physics. What is needed is cold hard facts. Remember that your teacher will give you a basic guideline of how your journal should look and a specific grading system for each. Most Biology journals require you have observations, a procedure and a conclusion. These types are graded very closely with how accurate you are in detailng information. So remember to have your journal with you when you do experiments. If you do not have it try to use your mobile phone to take pictures and monitor your progress. It should be noted that these pictures/ sketches should be included in your finalized journal. At times they serve for a larger project so remember to use as much detail as possible.
Art journal writing techniques are fairly standard. Some art teachers ask that you keep a sketch book/journal where you can place how you are feeling at a particular time. They also serve to record visits to a museum or when you study a particular art movement. For graphic design classes it serves as a way to jot down your ideas. Unlike most journals in other subjects, these journals are quite free and can be used for any purpose. Just remember to always have a certain level of organization.
Mastering literary journal writing techniques is the most difficult. Some literature teachers may ask you to write about a novel, grabbing on either personal experience or as a way to analyze characters. These are usually used for papers later on. It's important that you jot down relevant quotes and describe characters as much as you can. Usually, professors give specific guidelines. Make sure you use a good degree of literary criticism in your pieces and that your writing is well thought out and organized.
For creative writing journals, just write and await further instruction.
Don't go off topic. A journal for a specific subject is not your personal diary, so make sure you get your point across. Usually a teacher will monitor your progress, so don't worry about it being perfect from the start. Make sure you know your audience, your theme, and what you have in mind for your writing. The more you write, the better you will be. Often journals can be a great way to get extra credit!