We often see that people tend to brush their front teeth much better than their back teeth because they brush them first.
That’s why I would suggest tackling those hard-to-reach areas such as the inside surfaces of you lower teeth first. Also make sure you are brushing the junction where tooth meets the gum gently but thoroughly with soft-bristled toothbrush.
Let me know if you would like me to identify any problematic areas in your mouth so you can clean your teeth better at home.