Learn to control arms for solid impact
To hit the ball with power and control you need to keep your elbows tucked in close to the body, both going back and coming down. This needs to stick in the mind of golfers who tend to allow their right elbow to move too far away from the side.
To hit the ball solidly you need to keep your right elbow close to the right side on the backswing and your left elbow close to the left side on the follow-through until the clubshaft gets parallel to the ground. That eliminates immoderate arm motion, promoting a more compact swing. That also promotes a powerful blow as it allows your arms and hands to stay close to the body at impact. With your right arm staying close to your side it's easy to make a shot just like a hook in a boxing match that knocks out the opponent.
To learn to keep your elbows close to the body, practice swinging with the head cover of your driver tucked under your right armpit. This is particularly good for golfers standing over the ball in a bent posture. Moving your arms up without sufficient body turn causes the cover to drop out immediately. The cover will not remain on the backswing without a proper shoulder turn.
It's always good to keep your right arm from separating too early from your body. That's critical to making a tight backswing that leads to a spring-like downswing.
That also prevents you from swinging the club with your arms only as it encourages fuller chest turn, enabling you to start your downswing as a reflex action.
Similarly, for a well-coordinated downswing initiated by the unwinding force or reflex action, you need to keep your right arm close enough to the body to create a fully coiled body position at the top of the backswing, which underlies good downswing and powerful impact.
However, for a sufficient upward movement of your arms and hands you need to allow the head cover of your driver to drop at the top of the backswing. That is critical to producing distance if you stand over the ball in an upright posture.
For an ideal top-of-the-backswing position just picture yourself holding a mobile phone with your right hand to talk to your friend. That brings about sufficient upward movement of your arms and hands, allowing you to get the clubshaft parallel to the ball-target line without a forced effort.
Also crucial to solid shot-making is a slow swing tempo. Tempo varies from individual to individual but slow tempo is better than fast one. Maintain slow, smooth tempo during the entire swing. Slow tempo makes it possible to produce at least a decent shot despite a few swing faults.
Too quick a tempo restrains you from shifting your bodyweight to the right going back and to the left coming down. It's impossible to generate sufficient power without proper weight shift if you go for a two-plane swing.
Imagine yourself skipping a stone across a lake, using a sidearm motion. That image not only promotes proper weight shift during the swing, but also gets your right knee, right shoulder and right arm to move through the ball, which means that you release or fire the right side fully through impact.
More importantly, that encourages a good swing pace.
Recreational golfers tend to precipitate their upper-body turn at the early stage of the downswing. Unwinding your shoulders and upper torso prematurely causes your arms to follow, forcing you to cast the clubhead outside the ball-target line. That results in coming-over-the-top problem, causing you to swing down off plane and on an incorrect path that is from outside to in.
One of the good ways to prevent your upper body from unwinding prematurely is to initiate your downswing from the ground up; to do this properly, you need to stay solid on your right knee at the top of the backswing. That facilitates initiating the downswing by moving your left knee and left hip first toward the target, making it easier to swing down freely in the correct sequence.
Incidentally, to hit the ball solidly it's essential to start your downswing with a slight bump of your left hip toward the target. That allows your arms to drop inside the ball-target line, getting the clubhead to come to the ball from inside the ball-target line.
Also critical to consistent, powerful swing is to make it certain that your arms and hands do nothing but hold the club throughout the downswing, particularly at the early part of the downswing. Allowing your arms and hands to dominate your downswing impedes correct weight shift and solid impact. That also robs your swing of its proper path and plane.