Don't let anything (e.g. lack of the right approach) keep you from listening to people.
Only after you've spoken with 10-20 people will the advice in sales books (Founding Sales, SPIN Selling etc.) be valuable.
If, after hearing what those 10-20 people have to say, you've decided to focus on changing your product instead of selling what you have, you might try to implement the steps in "The Mom Test".
Disclaimer: random advice on the internet. Take it with a pinch of salt!