Let me write it down while it's still fresh in my mind.

趁记忆犹新，我来把它写下来。

Write it down word for word.

把它一字不差地写下来。

Write it down.

把它写下来。

Whatever you're planning to do, write it down.

无论你打算做什么，都要写下来。

Then I won't even write it down.

然后我就不会把它写下来。