Use this lat stretch to eliminate the need to bend your arms in the backswing and try this over the head hip and torso stretch to increase the separation between your hips and torso to make a more powerful swing
Keep your eyes directly over ball, shoulders parallel and putter face perpendicular to target line and head still
Push shots are caused by a swing that is too shallow and from the inside, many times caused by the body moving in front of the ball during the downswing and causing the club to get stuck behind the body