teeth whitener

So I don't really know where to put this but I'll ask anyways. I brush my teeth twice a day, I don't drink a lot of soda, and my teeth STILL have a yellow tint. What can I get to seriously whiten them? I've been to the dentist recently and he said there's nothing wrong with my teeth just to get a good cleaning every 6 months but my insurance only covers a dentist visit once a year☹️ any input would help!!