Brief Answer:
Reward for good behaviour and avoid punishments

Detailed Answer:
Hi
Welcome to HCM

I understand your concerns. As a first step in dealing with your child's sucking habits, ignore them! Most often, she will stop on her own. Harsh words, teasing, or punishment may upset your child and is not an effective way to get rid of habits. Instead, try the following:

-Praise and reward your child when she does not suck her finger. Star charts, daily rewards, and gentle reminders, especially during the day, are also very helpful.
-If your child uses sucking to relieve boredom, keep her hands busy or distract her with things she finds fun.
-No matter what method you try, be sure to explain it to your child. If it makes your child afraid or tense, stop it at once.

The good news is that most children stop their sucking habits before they get very far in school. This is because of peer pressure. While your child might still use sucking as a way of going to sleep or calming down when upset, this is usually done in private and is not harmful. Putting too much pressure on your child to stop may cause more harm than good. Be assured your child will eventually stop the habit on her own.

Finger sucking at permanent dentition can affect the shape of her mouth and how her teeth are lining up. So, in case you find any significant difference in roof of mouth or lining of teeth, then visit a pediatric dentist. There are devices that can be put in the mouth that make it uncomfortable to suck on a finger.

Hopefully this will help you. I would be happy to help you in any further questions.
Take care

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