You ask them how they are, you set time aside during meetings to be genuinely interested in them, and you openly share what’s going on in your life too! Vulnerability and honesty is important. 

Tools to me feel impersonal esp if it’s early stage startup

agree with all your points. tools do feel impersonal, but I believe if the communication is done right they can be a great asset too - e.g. for tracking progress and bringing a kind of order into the chaos.
it can be very subtle - something along the lines of heart rate monitoring with fitbit

Searchcaster