I certainly like the way Dr Maxwell Maltz put it in no uncertain terms, in his Psycho-Cybernetics classic:

THE FINAL WORD ON IMAGINATION PRACTICE

"... It doesn't matter how you describe it:

Imagination Practice, Visualisation, Mental Picturing, or using my terminology, Theatre of Your Mind

What's important is that YOU DO IT!

If you will choose a target to apply this so, and give it a solid, honest 21-day trial, you will be so gratified with the results that you will certainly choose to continue using this tool for the rest of your life, and benefit tremendously by doing so... "

You can say that again, Dr Maltz, for I have had been a full-time dedicated practitioner!