Behold...The Mighty Pencil!
(Of course you can use any brand of pencil although I prefer the Field Notes brand myself.)
You do this now whether you realize it or not. You might not put it on paper but, before you start coding something, you architect it in your mind. Definitely for some application development tasks, it doesn't take much thought to come up with a plan.
Here's a Life Rule for ya' :
If you can't explain it in simple terms, then you don't understand it.
Ye Olde Writing Device and Ye Olde Parchment can really help you understand your more complex architectures and tasks which makes it easier for you and others to understand. Simply writing your idea on paper crystallizes your vision and, very often, provides a springboard for the more detailed questions that don't come up until you start "seeing" how something is going to be built.
The ability to craft a vision and be able to communicate it to others is a skill set in shockingly short supply. A pencil and paper can really help develop that skill or spotlight your skills to others.
Plus, pencils are cheap and if you buy the right kind, the Cedar wood smells really nice.