Originally Posted by
PMDL
* Pause your calf work. Nice, long, deep stretched pause at the bottom. Big Achilles tendon = big stretch reflex, so you need to kill that stored energy. All the assholes you see bouncing the stack on those exercises aren't really doing much for the actual calf muscle, thus "they're hard to grow". Slow the reps down, pause, and use a heavy progressive-overload strategy like you would for any other muscle - sets of 5-12 reps and add weight when possible.
* Work both seated and standing variations. Bent-knee calf work will hit the soleus more and "thicken" them up.
* Get fat and walk a lot. If you have access to a weighted vest, that does the same thing. Other ideas are lots of walking on an incline, if you like the treadmill (maybe even holding dumbbells to add weight for a low-tech solution), or even hill sprints if you like the outdoors. Or just go for a walk around a really hilly part of town. This tends to complement the heavy strength elements of your calf training.
* Realize that most of it is just genetic. My wife never does a damn thing for her calves and they're her most noticeable body part. I can work mine every day and they'll never get as big as hers.