Try the five minute whitening gel that Walmart and Walgreens carries. If you go on youtube, you can find Kandee Johnson's video on it. Use the tray with the gel in the shower instead of just just for five minutes. I can leave it on for 30 minutes, a few days in a row. Once I achieve the shade, I just maintain by using in the shower once a week. I haven't been doing the routine much now, so my teeth are looking a bit less than white. I have sensitive teeth, but if they start getting sensitive from using it, I just switch my toothpaste from sensodyne. Doing it in the shower helps with that messy foaming at the mouth you do from having it in your mouth. It's super cheap and easy to find. =)