It is important to record the important events of your life; it is a great way of documenting your life. Whether you believe it or not, you deserve to have your life be remembered; especially if you are for bringing goodness to society and the world.
Buy multiple journals or composition book. Or create a special folder on your computer or USB for your .txt or .docx life logs. You can call it a diary, a journal, or a log. It's up to you - just make something in which you can store your entries.
Use one for your creative ideas. Whenever a creative idea pops into your mind, write it down or type it up. Put the date, sign your name. I don't recommend sharing your creative diary so that you can patent and copyright your ideas in the future.
Use one for your personal life. Record everything that you find memorable. Write down or type up your thoughts, your ideas, your observations, your memories, and everything else that you deem to be of importance. Date your entries. Sign them.
Use as many journals as you need; make as many files as necessary.
Protect your physical or virtual journals. Back them up, email them to yourself, hide them with your scrapbooks, buy a safe for them.
Don't share them unless you really want to. Maybe you'll decide to make some entries public when the time is right. Maybe you'll let people find them in the future, as if it were a hidden treasure. Or maybe you'll just keep them a complete secret.
Your entries will be something that you can look back at when you grow up. The passage of time overwrites and modifies human memories. With your journals, you may find something you can smile or reminisce about. Your journals will be something that other people can discover about you when you are older or even when you're gone. They will become your written legacy.
Whether you it digitally or physically, always remember to backup your life.