Make sure you always have the ability to take notes when ever something brilliant enters your mind. You need a “black book”. Some people prefer an actual note book (black or otherwise), others a few folded up sheets of paper, and yet others like taking notes with their Smartphones or online services for instant sync.
Either way, make sure your “note tool” is within easy reach. You don’t want to waste time looking for it, or even spend time trying to remember that great idea, if you can avoid it.
The reason these sudden ideas are so important to jot down is that they very often turn out to be the missing piece or ingredient to a project your working on. They may not look like much at first, but it’s likely that they at some point will be valuable to you.
It’s key to not have a system for note taking, free and unstructured wins! And never tie it directly to a project you’re working on. This allows the “black book” to serve as an inspiration/idea-container that you can revisit whenever you need some inspiration.