Objectives: Understanding how to help people form habits is important in improving health interventions. The impact of two behaviour change techniques on behaviour (cues and monitoring) was tested, and the role of psychosocial factors that may predict behaviour change and habit formation were investigated. Methods: Participants (N = 186) were randomised to one of six conditions (behaviour monitoring vs habit monitoring vs irrelevant behaviour monitoring and cued vs not cued) and instructed to engage in a specific, novel behaviour every day for the following 3 weeks. Participants completed measures of behaviour, habit strength, prospective memory, attitude, intention, self-efficacy and motivation at three time points (pre-, post- and one-week follow-up). Results: All participants increased habit strength and behaviour. Post-hoc, it was found that community members, compared to students, developed stronger habits and maintained the behaviour and habit strength at one-week follow-up. Intention, behaviour and habit strength post-intervention moderated behaviour and habit strength maintenance. Conclusion: This research furthers our understanding of how to help people form healthy habits. It was found that any intervention seems to be effective in forming a habit and changing behaviour. Moreover, intention, habit and behaviour were the most important predictors of behaviour change and habit formation maintenance.