Ross K,
First, some notes on abbreviated serves. These apply to all abbreviated serve styles.
When You Brings Hand and Racquet Together at Beginning
1) You want to
lower your right (service) arm over the left (tossing) arm. (This is different from classical, where you
raise the right arm over the left arm. You can verify the contrast in clips.)
2) Verify that your right shoulder is above your left shoulder.
When You Initiate Windup and Toss
1) Do not let the tossing arm fall when you initiate the toss. (This is different from classical, where you should let the tossing arm fall before taking it up.)
Takeback
Some people, when executing the abbreviated takeback, just go straight back with the arm, as if they're elbowing somebody right behind them. This is actually not right, and it's the #1 reason why people start "arming" the abbreviated serve. This wrong kind of takeback is similar to what a boxer might do to jab.
The takeback is more like the one when you apply a right hook in boxing. You should feel a "sideway" stretch around the juncture between the collarbone and shoulder joint. As with normal service technique, don't try to "guide" the takeback with your hand. Simply let the windup stretch the shoulder.
Visualizing that you're going to hit down on the ball helps too.
Now onto Monfils. The following stuff is loaded, but here goes . . .
Your Power Base
In terms of the kinetic chain related to the power base (core and lower body) of a windup, there's basically 4 major styles that pros use: "drive-platform" (Sampras,Monfils), "coil-platform" (Federer,Nadal), "drive-pinpoint" (Murray,Roddick), and "coil-pinpoint" (Safin.) When you use a "driving" style, it's somewhat like a groundstroke where you visualize driving in a line to the ball. Whereas when you use a "coiling" style, you're visualizing yourself turning and then uncoiling into the ball. Now, all four styles use a lot of hip and torso rotation and produce both linear and angular momentum, but the feel is very different.
The key thing is that you don't really want to flip flop between the four types. You have to reprogram the kinetic chain in your windup, and change up your visualization. It's a pain. So, I'll just show you the "drive-platform" style, which applies to both Sampras and Monfils.
Learning the Drive-Platform
1) Assume a platform stance for serving to ad court. Visualize the court in front of you
2) Focus on your hip. Start bringing your hip toward the court.
3) Focus on your belly button. Start twisting your torso away from the court with the belly button.
4) As you windup, visualize that you're leaping forward into the court.
5) Notice as you windup, notice how the weight falls onto the balls of your feet and how your knees bend.
6) Unwind and windup a few times.
7) Try steps 1-6, assuming a platform stance for service to deuce court.
You do this for awhile, and more or less you'll come to these principles for the windup.
If you're serving to the ad court,
1) Start bringing the right hip (right hip flexor) forward.
2) Start twisting the torso with the right side of the belly button (right oblique muscle.)
3) Do not let the left leg lock out.
4) Visualize driving into the ball.
If you're serving to the deuce court,
1) Start bringing the left hip (left hip flexor) forward.
2) Start twisting the torso with the left side of the belly button (left oblique muscle.)
3) Do not let the right leg lock out.
4) Visualize driving into the ball.
Bringing the Hands Together and Setting Up the Windup
After you've done the above for awhile, then you can also visualize doing this in reverse. And when you do it in reverse (belly button, then hip, away from the court), you'll notice that you get a positin somehwat like a Monfils or Sampras.
The above is what's done before you bring your hands together. It helps to set up the kinetic chain of the windup. Then, when you initiate the toss, the kinetic chain automatically starts in proper sequence. So, let's it put together . . .
Basic Abbreviated Serve using a Drive-Platform Base
1) Set up stance
2) Start turning torso toward court.
3) Bring hip away from court
4) Lower right arm over left arm. Verify that right shoulder is above left.
5) Toss (without dropping arm) and initiate windup. Note that your windup will already start as you toss the ball. Your center of gravity will be forward or in front of you. Your body will be already moving into the court as you toss and windup.
6) Visualize driving through the ball.
At this point, you may want to stop and just work on the above. It's pretty close to Monfils's serve. But if you really want to go further . . .
Monfils's windup includes elements for getting a heavier spin as well as good pronation.
1) As you windup, visualize applying backspin the ball. You'll probably feel a stretch around your lowest ribcage. This facilitates the racquet face sliding down on the ball, applying heavier spin.
2) As you windup, visualize that the ball is made of concrete. You'll probably feel a stretch around your collarbone. This faclitates pronation.
We add these two elements to the kinetic chain. This goes as follows.
If you're serving to the ad court,
1) Start bringing the right hip (right hip flexor) forward.
2) Start twisting the torso with the right side of the belly button (right oblique muscle.)
3) Start stretching/twisting around the lowest right ribcage.
4) Start stretching around the right collarbone.
5) Do not let the left leg lock out.
6) Visualize driving into the ball, with spin and pronation.
If you're serving to the deuce court,
1) Start bringing the left hip (right hip flexor) forward.
2) Start twisting the torso with the left side of the belly button (right oblique muscle.)
3) Start stretching/twisting around the lowest left ribcage.
4) Start stretching around the left collarbone.
5) Do not let the right leg lock out.
6) Visualize driving into the ball with spin and pronation.
Work through the windup motion for awhile.
Now, we put it all together. Just as before, you execute the windup in reverse and bring the hands together.
Monfils-style Serve
1) Set up stance
2) Start bringing collarbone toward court.
3) Start turning lowest point of ribcage toward court
4) Start turning torso toward court.
5) Bring hip away from court
6) Lower right arm over left arm. Verify that right shoulder is above left.
7) Toss (without dropping arm) and initiate windup. Note that your windup will already start as you toss the ball. Your center of gravity will be forward or in front of you. Your body will be already moving into the court as you toss and windup.
8) Visualize driving through the ball with spin and pronation.
And, finally, if you want to go for a "Roddick shoulder", ehhh I'll tell you some other time.