There is plenty to like about your serve: nice tossing technique, good racquet take back and swing with pronation.
Clearly you are swinging your right leg around too much.
And this leg swing is symptom that you are just swinging your shoulders from right to left
horizontally.
You don't have the
vertical shoulder over shoulder action of all really good servers, and as advocated by Jim McLellan in this video - not only because it gives more power, but is important to prevent incurring a rotator cuff shoulder injury:
Preventing Rotator Cuff Injury - You've Got to Drop the Left Shoulder
http://www.youtube.com/watch?v=lTRvxaBMh8s
And you are missing a major component of power in a serve: forming a "bow shape" in the trophy position, and then rapidly "reversing the bow".
Note that this reversal of the "bow shape" is initiated by throwing the left side of the body forward as you cartwheel shoulder over shoulder as just mentioned above in "drop the left shoulder."
Watching this video clip of Soderling Serving clearly shows this big body action:
Robin Söderling serve slowmotion
http://www.youtube.com/watch?v=a56pvP1i6x8
In other words, you want to get your trophy position to get to this bow shape and steep shoulder angle, so you can then reverse both in the serve motion:
Here's how to do it.
After release of the ball, keep bringing your arm up and up and up until it is straight overhead and keep it straight overhead (as you are already doing) into pic 4.
But then you've got to let your front hip protrude forward to counterbalance the upper body lean back toward the fence, as Will Hamilton from Fuzzy Yellow Balls urges in this video:
Tennis Lesson: Serve Tips: Lead with the Hip
http://www.youtube.com/watch?v=HgeYmEScfgQ
Notice that Sampras above "leads with the hip" in pics 5-9.
And that the only way to maintain your balance as you do this is to "bend your knees", as Sampras also demonstrates in pics 5-9.
Although the sensation you will have is not really "bending your knees", but that of doing a squat
but with your left arm raised.
(In fact if just do a squat with your left arm raised straight up, your front hip will automatically go out and you will form that "bow shape" - you don't have to push that hip out there at all - your body will just do it! Try it now and see!)
So that position of a squat with your left arm straight up is really what you are seeing as the aggressive trophy position in the pic of Djokovic above and pic 9 of the Sampras sequence.
[Notice also that the chest is pushed up at the ball, and to maintain your balance your heels will have to lift well off the court, with the lean back
not from arching the back, but from
leaning back at the knees.
Out of that aggressive trophy position, dropping your left shoulder straight down as you throw the left side of your body into the court will give you that vertical shoulder over shoulder action and dramatic "reversal of the bow shape" just like Soderling, Sampras and Djokovic!
One more thing.
Instead of swinging your right leg around as you now do, you will land more going forward, landing on your left leg, with your right leg extending back to counterbalance all that upper body weight going
forward (instead of just rotating around horizontally from right to left):
Leg Kick on Tennis Serve
http://blip.tv/fuzzy-yellow-balls/leg-kick-on-tennis-serve-1190196
I think everything in the following video reinforces what I've recommended above:
Nick Bollettieri-Sonic Serve.wmv
http://www.youtube.com/watch?v=ajoZ0f7hw-A
Good luck!
I've never had a day of "formal" instruction in my life, just self-taught. I'm not looking (yet) to add 30 or 40 mph to my serve, I just want to get the fundamentals down. Just looking for ways to improve, bad habits to unlearn, and have a solid form.
