To keep your bearings and YoYo running smoothly, you need to maintain your bearing. The best way to do this is to clean your bearing and relube it with the appropriate lube (and no, not that kind of lube - I'm talking about YoYo lube!)
If you have a responsive YoYo you will want to use a thicker lube, as this allows the bearings to grip a little better and provide more responsiveness (ie. the yoyo will come back up easier).
If you have an unresponsive YoYo you will want to use a thinner lube, which allows the bearings to run freely against each other, creating longer sleep times and more unresponsiveness.