Do you know what the most important thing is about the operation of a dryer? Drum roll please.........Air Flow! The venting on your dryer should be made of metal. The white vinyl duct that was common years ago no longer meets building codes.
If you are experiencing longer than usual drying times check the dryer vent, as restricted venting can cause air flow problems and fires. You will want to check the entire length of the vent pipe for lint build up at least once a year (more if it gets uses a lot). Using a vent brush remove any lint, do not push the lint back into the dryer, and watch out for any clogs in the vent.
After every drying cycle check and clean the lint filter on your dryer. If the filter has any rips or tears replace it with a new one. You can use a vacuum to clean the area that the lint filter fits into to remove any remaining lint.