Implementation Intention is a plan about where, when and how to act. It’s a technique that helps us follow through with our decisions and complete out plans, because Implementation is Better than Motivation
Formula
The broadest formula for implementation intention would be:
"In situation X, I will respond with Y"
But at the core it’s any concise plan that tells us what we want to do, and what are the triggers to do it. Other simple example is:
"I will do {Behaviour} at {Time} in {Location}"