yup, i agree. i have too much spin, so that it sometimes goes in the net...
i can't slice it too much.
my coach has also recommended just doing drills:
1. hold your racquet continental
2. do the back scratch (pull your racquet on your back with elbow beside your ears)
3. throw a ball in front of you
4. just come up with the racquet from behind and follow through
you can do this with just a normal open stance (shoulder width apart)
coach said this is a drill trying to teach you to put spin on your serve, hitting the ball like you're trying to slice it on the side.
what the ball should do is have enough spin to bounce about 6-8 feet in the air.
just a drill.
it helped me a lot with putting spins in my serves.