On my commute, I will often think of something that I want to remember (something I need to do later, something I want to look up later, or just an idea for some project).
In my car, I keep my iPhone on a magnetic air-vent mount where I can easily say “Hey Siri” to activate Siri. I then can tell it to send me a text message saying xxx, where xxx is the idea I want to remember.
I know there are many different ways to create such reminders (other than text messaging yourself), and there are probably ways that are even easier (or better in some fashion), but the key point is this:
There are particular times where good ideas naturally come to us because we are in a more relaxed/unfocused state of mind, but at the same time, we’re not in a position to immediately write them down (e.g., while driving or while showering). Thus, it is important to have at least some system to save those ideas for later, even if the system is not the “best.”
In short, don’t worry about which system is best, just try one out. If it doesn’t prove workable, try something else until you find one that does. Soon, it will be second nature and you’ll never lose any good ideas.
(For remembering ideas you get in the shower, see the post about remembering with mental imagery.)
One Idea 