I see a lot of people here trying to validate ideas and the usual advice is to always cold email people at first - which is okay advice, but cold email without decent context has a somewhat low response rate in my experience.
And because of this, I developed a simple formula to get early opinions (and leads) on any project using Google search operators:
"site:linkedin.com/in/ "NICHE OF YOUR PRODUCT" GATEKEEPER POSITION"
Just adapt this formula with your needs and copy-paste it on Google.
Now, here's a practical example of how did it for ecommerceranker.com:
"site:linkedin.com/in/ "e-commerce" CEO"
This way, I got over 8 million leads I could contact to get highly-relevant opinions on my e-commerce project. (and I even closed a deal with this strategy)
Just add 10-20 contacts (better if they're a 2nd connection of yours because they're more likely to accept your request this way), and politely ask them to review your project.
A considerable portion of Linkedin users accept connection requests within moments, so you can literally validate your idea in 2.5 minutes.
Now, if you feel Linkedin's not for you, that's also okay, because I bring you a second strategy involving Gmail accounts:
"site:linkedin.com/in/ "NICHE OF YOUR PRODUCT" @gmail.com"
This way you get the public Gmail addresses of highly-targeted Linkedin accounts you can email directly - and you also skip the waiting time of having them accept your connection request.
In my experience, 99% of these contacts are okay with being approached IF you say you saw their email on Linkedin - always give that context.
What do you think about this strategy?
Have you tried it before?