Deciding exactly when and where something will be done (ie, putting it on your calendar) dramatically increases follow-through.
Researchers studying implementation intentions discovered that:
Women who had set themselves the goal of performing a breast self-examination (BSE) during the next month…greatly benefited from forming implementation intentions. Participants in this study were first asked to indicate how strongly they intended to perform a BSE during the next month, and some of the participants were requested to write down where and when they would want to perform the BSE during the next month. Of the participants who had reported strong goal intentions to perform a BSE during the next month, 100% did so if they had been induced to form additional implementation intentions. If no additional implementation intentions were formed, however, the strong goal intention alone produced only 53% goal completion. [Gollwitzer]
In another study, researchers asked drug addicts under withdrawal to compose a CV:
One group was asked in the morning to form the goal intention to write a short curriculum vitae before 5 p.m. and to add implementation intentions that specified when and where they would write it. Another group was requested to form the same goal intention but with irrelevant implementation intentions (i.e., they were asked to specify when they would eat lunch and where they would sit). At 5 p.m. none of the participants in the goal-intention-plus-irrelevant-implementation-intention condition had completed the task. However, 80% of the participants in the goal-intention-plus-relevant-implementation-intention condition handed in their curriculum vitae. [Gollwitzer]
Gollwitzer, Peter M. 1999. Implementation Intentions: Strong Effects of Simple Plans. American Psychologist