Yamaha Watercraft Maintenance

I'm looking to get some feedback and guidance on maintaining my Yamaha watercraft. I've had it for a few years now, but haven't done much in terms of regular maintenance besides checking and changing the oil. I've noticed some slight issues with performance and I'd like to catch them before they become major problems. Does anyone have experience or recommendations on what specific tasks should be performed on a regular basis (e.g. every 50 hours, etc.)?