When I was in school, I heard this all the time but I didn't really understand what it meant. I never had an appreciation for it until I watched smaller, less creative, spit-shined ideas win out over huge, brilliant, messy ideas time and time again.
The difference between the life and death of an idea is often only how it is presented. And by this, I don't mean how pretty the powerpoint slides are.
I'm talking about finishing the idea. Working out the details. Playing devil's advocate and challenging the idea to see if it works under multiple scenarios. In user experience, beta stage is built into the process. That's ok when you're still concepting or in development stage. But by the time the idea is presented to the planning or creative director, or certainly the client, you had better finish the idea. If you don't, someone else will and you may not like it. Moreover, you may lose control of it.
Here's how you do that:
When you know you're on to something, it is not the time to STOP. It's the time to keep pushing. It's tempting to take a break because you feel as though you've found what you're looking for and you deserve a little reward. DON'T STOP. You are in the flow now. Get a cuppa tea and get back to it. If your brain is truly fried, run it by a trusted roommate or friend. Save someone super practical like your mom for last. They are good at fine-tuning and calling BS. And she's usually somewhere near the target audience. But if she doesn't get it, chances are--you're missing the mark.
When you find yourself saying, "Yeah I'm not sure how that would work." Find someone who can figure it out. Maybe it's a computer programmer; maybe it's an engineer. Maybe it's a doctor. Just go ask them. Quora can work really well for this too (online opinion solicitor/aggregator). If you don't have the wherewithal to solve the problem, or answer the question, find someone who can.
As creative people, the truth is, our ideas are never completely finished. It can always be made better. We see the flaws and struggles in our work. We often get caught in the trap of not finishing--not because we are tired or fried, but for the complete opposite reason--we are perfectionists. We think it's not ready to be shown or presented. It's not perfect. We are too attached. It's too tangled up with our ego. We are afraid to show anyone because we think they won't love our idea as much as we do. We fear rejection. We begin to self-sabotage. The negative self talk gets in the way, we get discouraged, throw out the clay and try to rebuild the whole thing again from scratch. The idea stays on life support when all we really needed to do was...
FINISH THE IDEA.