You should de-glaze the cylinder and replace the rings before you assemble it. Take the head to a shop and have the valve guide seals replaced. They're too cheap to bypass that step.
You won't be able to see the faults that cause the rings not to seal in most cases. However, smoke in the exhaust
can be used to diagnose the source of oil in the chamber. Rings normally tend to cause smoke under a load more than at other times. When they first start leaking, valve stem seals will cause a puff of smoke on startup after the engine sits a while. When they get a bit worse, you will see a puff of smoke as the throttle is opened after decelerating. If the seals are bad, but the rings OK, the smoke won't continue after the initial puff.