I have had great results in the last year using two tricks I found here from Phil and Dante (if I remember right).
The first trick is to forget about the stretch, when you go for the stretch, you are just using the elasticity in your achilles tendon to do the work for the muscle.
The second trick is to do standing barbell calf raises from the floor, no elevation under the toes, I do them barefoot sometimes, and in shoes other times.
Besides those tricks, I go deep into the pain zone, do drop sets, giant sets, high rep days, low rep days, all the standard stuff.
Thanks Phil and Dante!
edit: One more great trick! Train the SHIT out of your tibialis anterior, it makes the calf wider from both the front and the back, and is the area most people have the most room for improvement in.