You have been brushing your teeth at least twice a day for your entire life. So why can you still make mistakes while brushing your teeth?
In the morning you are in a hurry and in the evening you can't wait to plop in your bed. Chances are you won't get to brush your teeth for two minutes. Buy a toothbrush with a timer or set a kitchen timer in the bathroom to time your brushing from now on. And be a little hard on yourself.
Read also: "What happens if you don't brush your teeth?"
Always focus on a few teeth. If you have an electric toothbrush, you can hold it almost still; your brush does the work. Slowly slide your toothbrush to the side and focus on a number of teeth until you have brushed your entire teeth.
There's no need to scrub hard on your teeth. Brushing too hard can irritate your gums. Light pressure is sufficient.
Most people have a mirror above the sink. Use it while brushing your teeth. Where does that toothbrush actually go? And have you also brushed all the edges along your gums well?
You cannot reach the spaces between your teeth with your toothbrush. A breeding ground for bacteria. Bacteria feed on sugars, they attack your tooth enamel and cause cavities. In other words, flossing or toothpicking isn't just for the week before going to the dentist, you should be doing it every day.