To be straight foward, the question is how to advance after the research, creating and prototyping. The next steps requiere money and some expertise which are not easy to have nor find
It is tricky but not possible.
Having been in your situation I can appreciate the challenge that lies ahead.
Investors took for signals to create reassurance and trust, things that are generally tangible like an MVP, initial customers, the first proofs that customers are willing to pay and a problem is actually being solved.
Not having that makes it a magnitude more difficult so having a proxy for those tangible signals will matter most.
For example to make the product more real without a product you may want to create a clickable demo to give investors a feel for the user experience and how it will work.
If you don't have customers yet then maybe you can survey the market and potential customers and reference those that provide good feedback and interest in your deck.
Other positive signals will be useful too.
Very importantly, at an early stage, investors are backing the team even more than the product. Having a solid team with sector experience who have created a startup before and have the experience needed will be very important.
In terms of investors focusing on friends, family and creating an offering that is derisked and maybe has task incentives can help get some initial commitments. Smaller tickets will help.
Also if you have invested your own money and have committed to not taking a salary or taking a greatly reduced salary for an initial period will show investors that you've got skin in the game and you're prepared to lose your own money.
Finally, investors like to see other investors invest, when there is momentum and fear of missing out investors may be more motivated to invest.
Give me a call if you want to discuss further how to create a solid MVP stage fundraising strategy