It's better to determine the cause of your child's tooth discoloration. It may just need some scaling and polishing( professional cleaning). Please take your child to the dentist for the appropriate treatment for her age.

Start using toothbrush as soon as they have teeth.

Children at this age are motivated by fun and reward so you can incorporate this into tooth-brushing time.Make it fun, play music or sing a song like "This is the way we brush our teeth, incorporate your child's name. Give praises at the end of the activity. You can create a tooth-brushing chart where you put a smiley face, a tick or a sticker when you finish brushing your child's teeth.