A tension filled grip, especially from having the shaft too much in your palms, will kill your entire swing. It stops your wrists from hinging naturally and then works its way up your arms and into your shoulders and locks up your entire swing.
A waggle is a great preparatory motion to get your wrists, elbows and fingers loose and ready to swing
On your takeaway, when your club is half way back the shaft should be parallel to the ground and the clubhead should be even with your hands, not inside or outside of your target line