In one study, experimenters distributed coffee reward cards, with 10 stamps earning a free cup of coffee.
Condition 1: a 10-stamp card with no stamps filled.
Condition 2: a 12-stamp card with two stamps already filled in.
Participants in the second condition purchased more coffee and at a higher rate than participants in the first condition. Furthermore, participants accelerated their coffee consumption when they got closer to their prize.
Ensure the first step of any journey is simple to accomplish and continue to recognise progress along the way. Avoid making people feel they are starting afresh.
Excerpt from: The Unseen Mind by Ogilvy UK