The best advice I can give you is to just find a journal and pen that feel comfortable and start writing. Other than making sure that you date your entries, there are no rules to keeping a journal. It can be a spiral notebook, a fancy book or even a computer file. Some people like lines, some prefer unlined pages, some like to type their entries and still others prefer a combination of two or more. The important thing is that you're comfortable using the journal you've chosen.
Size is also something to consider when choosing a journal.
If you plan to carry your journal with you at all times, then you will probably want to select a journal that is smaller and easy to carry in a backpack, purse or briefcase. On the other hand, if you're primarily going to be doing all of your writing in one place, such as your desk or kitchen table, a larger book may also be an option. If a computer journal is what you're interested in, there are several journal-keeping programs available that you might be interested in trying. Yeah Write , Vista Write and LifeJournal are three such programs which have trial versions available for downloading online. If you want to share your writings with an audience, creating an online journal may be the thing for you.