Think BIG, act small

First heard this sentence ’think big, but act small’, I am totally inspired. Why?

I am a trainer, and have many friends like me as trainers or consultants. Often I have some ‘great’ ideas, but I didn’t move forward, so I would miss some opportunities as well. Then if I have any idea, and would like to make it real, and I have to do something, aka. act a small step.