Your idea is important.  Even if you think it is not. 

Prototype.  This means draw, build, model, or hack together something that resembles the essence of the idea.  Don't worry if it looks hacked together.

Tell a story with the idea.

Everything worth doing is worth doing poorly.  Deliver half the product, not a half-assed product.  Put more importance on things that pop into your head.  Make some mistakes.

Put it online.  Putting your idea online forces you to consider the usability of your idea.  It forces communication.  We all have ideas.