I like to think I have a good routine, but regardless of training style the most important thing is consistency. Show up every time you've scheduled yourself to do so. No matter what else is going on, barring injuries, be sure to hold those appointments.
Now, since you're busy this will be harder. Maybe you could set a couple of days as your workout days and have a floating day for when you have time? Just a thought.
After a while it will become a habit, and eventually it is second nature. I'm trying to develop my cardio as a habit. Hopefully in a couple of months it will be.