Praise and reward your child when she does not suck her thumb or use the pacifier. 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.
If you see changes in the roof of your child's mouth (palate) or in the way the teeth are lining up, talk with your pediatrician or pediatric dentist. There are devices that can be put in the mouth that make it uncomfortable to suck on a finger or thumb.