Flossing
Flossing is generally regarded as a painful and boring routine which few adhere to.
The secret is to do it lightly to prevent pain and discomfort which will actually clean the teeth via the gaps.
A common mistake is to leave the teeth at the back out because they're hard to reach. But this is precisely why it's important to floss there - this is where most of the chewing takes place and therefore where most of the food gets stuck.