In the ready position…
a. Position your racquet head up (slightly above the level of your shoulders).
b. Position your hands and elbows out and away from your body.
c. Set your weight on the balls of your feet.
d. Position your feet in a slightly wider stance with more flex in your knees and a lower center of gravity than the ready position for the groundstrokes.
e. Stay light on your feet ready to move quickly (in, back, left or right) to hit your volley.
Use the continental grip for both the forehand and backhand volleys. Position the base of index knuckle and the heel of your hand on the second bevel of your racquet handle for the continental grip.
Hit the backhand volley with one hand (not two hands) to better respond to balls hit out of your strike zone including balls hit at your body, balls hit wide left (or right), balls hit low at your feet and balls hit high well above your head. To transition away from a two-handed volley, practice hitting the backhand volley with your non-hitting hand placed behind your back.
Set the racquet in line with the ball with no backswing in preparation for the oncoming ball. Position your eyes and head in line with the ball (lowering your center of gravity with a wider stance as necessary in response to low balls). Ideally, you would like to see the ball through the strings of your racquet at contact.
Catch (not punch) the ball at contact. Preferably maintain a 45 degree angle with the racquet at contact.
Lead with the butt end and bottom edge of your racquet to position the racquet with an open face at contact. Keep your racquet head up and maintain an open racquet face at the conclusion of the shot.
Set the wrist of your non-hitting hand close to the wrist of your hitting hand as if your hands are handcuffed together for the forehand volley. If you have a problem with your non-hitting hand rising up at contact (not an uncommon problem for the forehand volley), cross your hitting arm over you non-hitting arm at contact as a corrective technique. For the backhand volley, use your non-hitting hand to position your racquet in line with the ball. Separate your non-hitting hand (bringing the elbow of the non-hitting arm back as if you are drawing an arrow in archery) as you start your forward momentum.
Whenever possible, move in on the diagonal stepping with your opposite foot to hit both the forehand and backhand volleys. Close with the shot (particular for balls in your stroke zone).
Never hit the volley from the same position of the court two shots in a row. Close in to the net, retreat back from the net, etc. as necessary after hitting each volley in a point sequence.
When not in a position to win the point with the volley, hit for depth and/or keep it low and in doubles, keep it away from your opponent who is closest to the net. When in a position to win the point with the volley, attack and/or hit for angles and in doubles, hit for openings or go at your opponent who is closest to the net.