Visualization is CRUCIAL!
Also, this is the KEY to how I've accomplished some things.....I visualize from the First Person (same as what we've talked about in the phrasing aspect). What I mean by that is....When I'm visualizing myself on stage....It's not that I see annie up there doing her thing.....it's from MY EYES! I see the audience, the bright lights are shining in my eyes. It's from my perspective...from the back of my eyes and not from the audience perspective. That way IT"S REAL! If I'm really onstage....then that's the way I'll see it.
When I made the switch (from 3rd person to 1st person) it became MORE POWERFUL!

Things for me started happening much quicker, and I had always visualized before, just not this way.
I thought about what you wrote Akashic Librarian...and I'll have to politely disagree on your percentages.
It's 100% voicing it (either through voice or writing)
It's 100% action (how can it happen if you don't take action??)
It's 100% visualization (It you can't "see it", you won't believe it, nor will you take action)
All three things are Crucial!