Invest in one of those small hand-held mirrors like your dentist uses in his office. It can help you to spot plaque and tarter build-up in places not accessible to the naked eye and can assist you when you've got something stuck in between teeth. You can also use it to inspect your mouth for anomalies that may indicate underlying health issues.
To maintain dental health, do not neglect proper flossing. If the floss you are currently using is too thin to adequately get between your teeth, try switching to a thicker kind, such as dental tape. Alternatively, you try doubling the strand of floss in order to achieve the desired thickness.