My dental regimen is as follows.
Brush without any toothpaste. Then floss. Then rinse with 3% hydrogen peroxide diluted by 50% for 30 seconds or so. Then brush with a fluoride toothpaste. If you're not a fan of fluoride, then make sure your diet is high in minerals to compensate.
The peroxide will kill all bacteria along the gum line, and whiten teeth. Mouth washes have peroxide, but they also have alcohol which dries out the gums and causes recession.
Some people use baking soda for the first brush, but I find it too abrasive. If you have sensitive teeth, I don't recommend the peroxide every day because it will corrode your teeth.
If your teeth are soft or yellowish, then your diet is too high in acids and sugars. Bones (including teeth) are comprised of hydroxy-appetate, which is largely calcium and phosphorus. Eating more greens, especially kale, broccoli, romaine, and spinach, will increase the levels of these minerals in your blood, which in turn are secreted in saliva. This will make your teeth harder and shinier. Also very important - if you don't have regular exposure to sunlight, take 2,000 IU of vitamin D each day with food, and this will increase your body's calcium absorption.
You can also apply a topical application to harden teeth. Buy some organic kale and spinach. Take a piece of each and form it into a ball, then chew it in your mouth into a bolus. Pack this chewed bolus into cheeks, either along the upper teeth or lower teeth, and leave it in for as long as possible. Let the saliva fill your mouth and swish it around. If you have a night guard you wear to prevent grinding, you can even pack the veggies into the mouth guard for the night.
Yes, your teeth will look green until you rinse your mouth out, but the minerals in the veggies will help to mineralize your teeth. They'll feel hard after the treatment is done.
This is all stuff I do personally so I know it works!