In the appropriate app/settings? This has nothing to do with the device, but rather the app that sends push notifications. And since you didn't mention which app you want to stop sending push, we can't be more specific than this...
You could also go for the brute force way and disable Google Services Framework and Google Play Services.
But.. No Play Store after, so not a that good idea. ^^
Might work for some apps, but I know that it doesn't work for WhatsApp. I usually have them disabled and enable them only to access the Play Store. Best option is to configure each app as stated above.
MB525 - Bayer Camera - Slim-mb526-4.4.2.beta.2.4-UNOFFICIAL-20140120-1830 Sony Xperia TX LT29i - CARBON-KK-UNOFFICIAL_Hayabusa_build7
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