Every material is different, and some things can be applied only to certain materials in a certain way. When dealing with leather for example, you should also be very careful, for it can be tricky to work with.
Best way to approach this is to combine warm water with some type of vegetable-oil based soap. Once cleaned and dried, it’s time to address those nicks, dents, stains and scratches.
Take some mayonnaise and spread it in a thin layer over the ring. Leave it there for about half an hour, and then wipe the piece of furniture off. The water ring should disappear with the mayo.
Best way to remove stains from the furniture is to make a mixture of ¼ cup of canola oil and ¾ cup of vinegar. Apply the mix to the cotton cloth, and rub it in circular motions on the stain.