The most effective habit is to clean gutters and roof valleys regularly and trim nearby trees. Gutters are like the drainage system of your roof. When leaves and dirt fill them up, water carries debris back onto the roof surface and creates little piles where moss and rot thrive.
If you can safely reach the gutters with a ladder, clear them at least once or twice a year, and more often if you have big trees nearby. Use gloves, a scoop or even an old plastic container, and flush them with water to check flow.
For the roof surface itself, avoid walking on it unless you know what you’re doing. Light debris can sometimes be blown off with a leaf blower from a safe spot, or a professional can handle it as part of a periodic roof service.
The combination of trimmed branches + clean gutters + occasional visual checks keeps most roofs relatively free of debris without turning it into a full-time job.