Language Point 21

When a good idea comes your way, write it down — on your arm if necessary. (Para. 8)
Meaning: When an idea occurs to you, you must write it down and if necessary write it on your arm.
come one's way: occur so that one has it or gets it
You have to get yourself ready for any time; when a chance comes your way you can surely capture it. 你必须随时作好准备；一旦机会来了，你就能不失时机地抓住它。