I learn to serve back in 1962, so I learned under the rule of one foot in constant contact with the court surface, not allowed to jump. So, this
led to using a pinpoint type serve to increase leg drive and landing inside baseline with my right foot. Using momentum I was able to go high on
my toes of both feet after bring rear foot forward into a deep knee bend (knees bending towards right fence at about a forward 30-35 degree
angle) really pushing up with the back leg, my body would lean over the baseline caused by the left hip moving forward. If there was no ball to
hit, I would have probably fallen flat on my face. However, as I push down on the court with the rear leg, the deep trophy position I was in caused
my body to lean far past the baseline as I finished the serve. At the time I was 6 foot 4 inches and my contact point with the ball was about 9 feet
to 9-6 inches above the court.
I was asked by an X-Pro to help teach his students because of serving ability. The X-Pro saw old still photos of my serve and commented one
about the forward and up diagonal push and two that my racquet hand palm finished parallel facing the right fence. I still use basically the same
motion today. However, I can use a jump motion landing on the left foot, but it is too tiring at age of 71.
Now the toss motion can be parallel with the baseline or more to the front. If parallel, the ball travels up and also out in front in an upside down
letter J. The ball comes back toward your body so that as the hips and shoulders uncoil the ball is directly out in front or over your right ear. Now
I prefer directly out in front over my head as I can use the same toss for more than one serve, not giving away whether I am hitting flat, topspin
slice or kick. Now, a quick note, if you want to hit American Twist, you don't really need to arch your back. Just a deep knee bend which causes
your back to angle to the left side of the court, but allows it to remain relatively straight. Then keeping the left shoulder facing the net hammer
up and pronate. Don't allow the shoulders to rotate towards the net.
Regarding the concept of hammering. Let's call the Continental Grip a hammer grip. Most of us have used a hammer at some point in our life.
Consider this, using a hammering motion, the edge of the racquet is leading. The racquet is directly behind the right shoulder. In fact you could
grab the racquet head with your left hand under your right armpit. Get the picture? Now as you hammer up at a nail high on a wall (as high as you
can reach) the problem is the ball toss is on your left side, thus uncoil the hips and shoulders and pronate (forearm rotation) to bring the strings to bear.
The problem I see the most often is the racquet take back ends up with the racquet head behind the left shoulder or mid-back with the strings
facing up towards the sky. If your doing this your pushing too much air resistance and the centrifugal force will move the racquet head out and
away from you body making it hard to pronate as your forearm is forced to resist being supined. Therefore, try to keep the racquet head as
close as possible behind you right shoulder, depending on you flexibility. Also, lead the hammer high on a wall motion leading with the racquet
edge.
Once, the pieces of the entire serve are put together and you have a relaxed fluid rhythm, the ball toss becomes almost automatic as you
will find where the ball needs to be in order to hit it.
I could go into more minute detail as the serve has always been my favorite stroke, especially since I played serve and volley on fast hardcourt.
Why go into long baseline rallies when the point could be won in 2-3 shots. You know, serve, approach volley, and volley put away, point over.
Next, rinse repeat. Thus old time serve and volley players make good doubles players because their schooled in get to the net pronto.
Good luck developing a consistent toss. However, concentrate on the service motion progression. The toss will take care of itself.
Aloha