for which product? which industry? target market? I'd need more info to answer your question.
Also, Arbaaz, I just launched and could really use your support by leaving a honest review. Would that be too much to ask? Thank you.
https://rb.gy/ae6hp
In my experience messaging people on LinkedIn works better because they are one click away to see your profile which has all your history on it, probably increasing the trust factor or at least think of us as humans not an email.