Play with your ideas. Don't be afraid if they come out wonky--be fearless! Ignore the odd, clunky, dangly bit you included for no discernible reason. You can remove it later if you find it doesn't fit--that's what revisions are for. Be proud of your work even if it's awkward and lopsided. You're finally doing something with all the stray bits you've had lying around waiting to be given a shape.
Now, get serious. Your idea is viable. You can do it. The premise is solid, and your vision is beginning to coalesce. Take note of key elements that pop into your head, pinpoint them, then use that framework to create your arc.
Once your project has a rough shape, step back, drink coffee, save a copy of your work, and ponder what you've done. Think. Plan. Then, get back to work, cutting and smoothing out rough edges--but don't toss the scraps! You might need them to bind loose ends.
Now for the fun part: make your work pretty! Don't weaken the structure by removing things willy-nilly, but do replace mundane bits with bits that zing or sing or twirl. Don't be afraid to experiment! After all, nothing is being wasted. If one shape doesn't work out, simply bend your medium into a new one.
When you've done everything you can it's time to lift your project into the sunlight and see if it can carry it's own weight. Check for gaping holes. If you find them, fill them. You're lucky--you're working with a flexible medium--everything can be fixed with a little thought and elbow grease. Ask someone else to take a look. Then someone else. Listen, learn, improve your project.
Make sure that the important connections are there, inextricably intertwined so that no part is complete without the others. Then take one last look, clip a stray tendril, and turn your back, and walk away.
It's out of your hands. You can help it along, sure, and take an active part in its care. Invite people to look at it if you'd like. Hope they can appreciate the work you've done. But mostly, try to keep a smile on your face, and cross your fingers that something beautiful will grow.