One of my all-time favourite quotes:
“Paper is to write things down that we need to remember. Our brains are used to think.” - Albert Einstein
This is how you can capture your ideas as they pass through that piece of meat between your ears.
But, even this isn't enough... you have to act on them before they pass their expiration date.
"Ideas have a short shelf life. You must act on them before the expiration date." - John C. Maxwell
Millions of life changing ideas are thought every day.
Few are materialised.
You have to pride yourself on more than just those ideas, you have to pride yourself on how you execute them.
And once they hit your mind, the clock starts.
If you don't strike the iron whilst it's hot, if you do not give energy and action to the thought whilst it's fresh, whilst the timing is right, whilst it's relevant... consider it as good as gone.
Now, it's important to note: Some ideas are better gone. You cannot act on every thought you have, because you only have a limited about of time and energy to spare.
In-fact, keeping your focus small means you can give what it's going to take to make that idea a reality.
But, when the good ones do come - the ones that you know can and should materialise in the world - capture them and take action on them whilst your energy is high, before it fades into storage with the other unused ideas.