Good form and complete reps!!!
Every rep should be paused 3-5 seconds in the fully stretched bottom position then you should explode into full extension.
In my quest to beat shitty calf genetics I have tried many things. What is currently working for me.......
Standing calf raises - One set rest-paused. Basically pick a weight in which you fail at in the 10-12 rep range with perfect form. You do one set to failure, hop off of the machine, take 20 deep breathes, and then repeat for two more mini sets. You should try to get 30 reps within the three mini sets of the rest-pause. Once you get thirty add weight next session.
After the rest-paused set do 3 sets of 6 to 8 reps of seated calf raises as heavy as possible. Don't let heavy weight make you use shit form.
After the one rest-pause set and the three sets of seated raises stretch each calf on a block individually for 60-90 seconds.
I typically do this once a week and it is working for me. Expect some soreness the day after.
Also walking on an incline treadmill and hill sprints will make your calves swell up too.