Generally a splash of lemon or lime.

Once in a while add a little cold left over coffee. Makes kind of a coffee cola.

We bought some artificial flavors from the cooking section of the grocery store and I use them once in a while but not too often. They kind of give an essence of flavor with more smell than taste.

Sometimes a little salt. Redmond salt.

Now I like it just plain about as well as anything.

You can buy commercial soda flavorings but I never have. I assumed most if not all have either sugar or sweeteners.

John