There are definitely multiple ways !!
. Go to kickstarter and indiegogo and see if there will be backers or no
.Try to go for a roadshow and see if there will be a series A investors or no ( investors know alot about the market ! Even better than you sometimes)
. Check the comparatives / Competitors
. Do market research / study groups
. Go even to your future target customers , and see their input and hear from them
. Create an MVP ( Minimum Viable Product) and start doing sales. It is called MINIMUM for a reason