1. Talk to your dentist in case you have gum disease.
2. Floss twice daily. You can run the floss through some mouthwash before using for extra effectiveness. Pay attention to ill-fitting crowns as you floss: they may need dental work.
3. And if all else fails, you simply use the magic cure. It really is magic, but it's hard to find. I've been recommending Lavoris for years, and I've had women come tell me that it saved their marriage. My own hubby uses it, because he's paranoid about his breath.
It's full of food coloring and sickly sweet, but it really works. Gargle before bed. Oh and don't use the mint flavor, only the cinnamon seems to be effective.
If you can't find Lavoris in a tiny little mom and pop drug store, ask the pharmacist to order it for you.