I've read a couple of threads on here about Pete Sampras and the 'heavyball' serve (speed and rpm), but I don't know what makes (or how I can serve) an effective 'heavy' ball (at my standard of 3.5/4.0, that is). After spending months on my service action, I'm pretty confident with it now in terms of going for the big serve, but I can't put any topspin on it (that is, I don't use a classical topspin-serve action). Nearly all of my serves are 1st serves (for both - I find it impossible to compromise on the 2nd serve - hence I still get more double-faults than usual) and I pretty much use the slicing motion/action every time to achieve balls that go 'in'. I rarely go for the 'flat-bomb'... I'm 6'3, 200lb and tend to get quite a bit of 'kick' off certain serves - is this due to the extreme slice I put on, my height..or both? Am I using the correct method(s) to serve a 'heavy' ball?