How to make it a practice? Take a week to pay attention to when you have a little pocket of time. I fit mine in on Saturday mornings after the first dog walk and before the family wakes up for breakfast. Then dedicate that time to those 12 minutes week in and week out. Before you know it, it will become routine!
How to use it in between meditations? Writing things down helps us learn and retain information so use a journal (go ahead and treat yourself to a new one or break out one you've squirreled away for Special Occasions -- new month, new me!) to recap the meditation. That will help you remember the key points as you're stuck in traffic or walking the dog or in the grocery line. How lovely for those to become opportunities for a brief meditation!