I checked out most of the suggestions and they are all pull strategies hoping you will lure investors at this early stage to do that you're going to need quite a bit of marketing and factor that into your funds you're raising in order to see how much you can afford for onboarding acquisition costs. Its a bit of a gamble also

You're probably not going to like this one but the best is to opt for a push strategy and to 1 to 1 outreach. Make a list of investors you think would be keen and have stake and approach them 1 by 1, from those who are not keen ask them for a recommendation and then add it to your list. I know this is painful and not the traditional glamorous crowdfunding idea we've been sold but it does work!