Do you drink enough water? At least 1.5 to 2 litres per day is the recommended amount. I have a pint glass of water next to my computer which I try and fill at least twice throughout the day. In the colder months, drinking so much water this way would make me feel really cold. So to keep warm, I drink water from a thermos filled with hot/boiled water. If plain boiled water does not appeal to you, why not put a slice of lemon in a mug (or inside your thermos!) and pour boiling water over it. (Tip: store lemon slices inside a plastic bag in the freezer for a constant supply of fresh lemon).
Also, did you know that coffee/tea will eventually stain your teeth (so will red wine in fact)? If you can dye a bra with tea bags, imagine what drinking tea can do to your teeth over time! So, to keep your teeth looking white for longer, try and limit your consumption of such drinks? Or at least, avoid “rinsing” your mouth when drinking them. By “rinsing”, I mean moving liquids through your teeth towards the front of your mouth before swallowing.
Have you tried fruit or herbal infusion instead? Shops have a large selection. Or, just get used to drinking water on its own
Some food for thought anyway.