Some great tips already listed here. I'll add one additional tip that cuts through everything that is simply sell your product. If you can't sell it to at least one business (if a B2B) or to 10 consumers (if a B2C) then you won't be able to sell it to thousands. I'm in the business of helping validate ideas and selling is the best measure. Best of luck and if I can be of help, please connect via my site http://TryHypothesis.com