I doubt you can afford it unless you are in college, but the best option is to get a tablet PC... you never lose anything unless your hard drive crashes, there are back packs available to carry them in and you can take your notes by writing on the screen and then save them in your own handwriting.

Besides doing that... there aren't any very good methods, I would try the planner, and definitely use a folder or two.

If you need to, keep several folders, choose a different color or picture for every class that you have and purchase a matching notebook where you will keep your notes.

Keep about 3 or 4 pages blank at the front of the note book. Every day make a new entry at the top of a new page with the date. Write the page number at the bottom of each page, then go back to the beginning after class and write down at the beginning what you studied that day as a title, put that in quotation marks on the left hand side of the page, skipping a row each entry

then in the middle of the page write the date, then the page number on the far right.

Each time there is a test draw a line along the bottom of the last entry before the test, not crossing out the entry.

If there are assignments, feel free to write down the assignments in your notebooks table of contents.

Then organize your folder chronologically, and number the pages. Keep work that you are trying to finish on the right side, and finished work on the left.

You should keep all tests and returned homework in the left hand pocket of said folder.

When you need to review for tests, all of the material should be easy to find and chronologically available.

Hope this helps.