When Maintaining Ketosis, How Do You Prevent Gluconeogenesis?
At Least Not 24/7 forever and ever. There will be occasions that GNG is going to happen, whether you like it or not.
By sticking to the Keto and becoming Keto Adapted, however, you will reduce and all but eliminate these instances.
You will find occasionally, that a particularly intense cardio or rigorous resistance training session will move you temporarily out of ketosis and into GNG, but this is not unusual and is more-or-less prevalent depending on your genetics, your level of Keto Adaptation, intensity & duration of exercise.
I have also found a dose or two of MCT Oil very useful for getting myself back on the wagon quickly.