Dental floss is an important part of oral hygiene armamentarium. It complements what toothbrush does and helps you clean areas of teeth that is not reachable by toothbrush.

A good toothbrush should reach most of the visible tooth surfaces. But even the best toothbrush is not able to reach the areas and surfaces in between the teeth. That is when dental floss comes in handy. 

When using a dental floss, always start from the same point. The goal of flossing is not to put pressure on the gum or clean the space per se, rather it is to reach the two surfaces on each side of that empty space. So when flossing, make sure you place some pressure adapting the floss to each side of the empty space on each tooth.

In a way the floss should 'hug' the tooth and the movement is applied to remove plaque from that space. An approximate 12" piece of dental floss should be rapped around the middle fingers of both hands and using thumb and index finger you should guide the floss in between the teeth one by one.

Flossing once a day (if it is done thoroughly) should be enough.