It has been said many times on the board, but the 'sound' of impact, of proper impact, is something 'most' people haven't heard.
I highly recommend working with just your putter on an indoor practice mat, keeping down, out, forward and 'feeling lag pressure in your hands' - until you 'hear' impact.
Chances are, you'll know it when you hear it
Down, out, forward - hands leading - lag pressure points in the hands
repeat
Down, out, forward - hands leading - lag pressure points in the hands
let the club 'swing'
Support the on plane swinging force in balance
I highly recommend working with just your putter on an indoor practice mat, keeping down, out, forward and 'feeling lag pressure in your hands' - until you 'hear' impact.
Chances are, you'll know it when you hear it
Down, out, forward - hands leading - lag pressure points in the hands
repeat
Down, out, forward - hands leading - lag pressure points in the hands
let the club 'swing'
Support the on plane swinging force in balance