I have an idea that I believe will benefit two target markets (don't we all). I have tried reaching out to one of the markets (food truck owners) online (email & Facebook): 4 in total so far. None of them responded. Is it because there's something wrong with my message to them? How do you get to the right people to validate your ideas? Do you try all sorts of methods before you finally give up? Is the lack of replies an indication that my idea won't work, am I executing my outreach the wrong way or do I just need to try to reach more people?
One of the best ways to get some much-needed feedback is with a beautifully designed survey (because something that looks good is going to be better than random Facebook messages). It also shows you're committed to the idea and professional. You could send the survey link to business pros on LinkedIn (normally has high engagement), through email or even your personal social media pages.
An easy-to-use survey option is Fieldboom: http://www.fieldboom.com. Their site also gives tips on getting feedback and how to build a small business (once you really get started).
Hope that helps!