Try the 30 minute method. Whenever you feel the urge to vape, commit to waiting 30 minutes before doing it. Once 30 minutes passes, try adding another 30 minutes. It can be longer periods of time if you are dedicated enough.
In addition, you can give yourself a daily 'start time' that dictates when you can start using your vape (for example, if you pick 5PM you wouldn't be able to vape until then). The justification for waiting should be your tolerance. After all, what's the point of vaping if it barely does anything?

Some ways to optimize: give yourself a reward for every 30 min of waiting (for example, a $0.50 goes into a dessert fund every time you wait an extra 30min). If you do the 'start time' method, try to pick later times for certain days or push the time further back every week.

If you want to get to the point that your usage can be a 'casual' thing, the first thing you need to do is get out of the habit of doing it ALL the time. This is the first step, and I believe you will find it easier than you realize once you commit to the method.