The painful fact is that you'll need to make headway developing your product and getting customer feedback before you're in a credible position to obtain angel or venture capital funding for your business.  So bootstrap and/or leverage friends and family, and be as creative as you can to keep expenses down.  Your challenge is to develop at least a prototype so you can get customer feedback.  (Better yet, get customer orders!)

And (we hope) you've done a lot of work to validate your market.  That's good.  But don't think that you can ignore customers now while you go off and develop a product.  Customers will not be ready for it unless you stay engaged with them while the product is under development.  So while you're developing your product or service, you also need to be engaging with customers.  (And "you" in this case means the founder/visionary.)

And while doing all the above, you need to run lean.  Because you're going to make mistakes, you're going to do some direction-changing, and all that will take longer than you think.  So keep your burn low early on.

Steve Blank wrote extensively on customer development in his book The Four Steps to the Epiphany.  We'll be summarizing his ideas in additional pages. (Look for more content soon.)

And check out our introduction to the lean start-up.