To maintain the shining surface of furniture keep dusting it regularly. Never let dust make a layer over furniture it not only lessens the shine of furniture but also damages wood.
Never satisfied with just a good paint, furniture requires more than that to last long in its original form. You should clean it with water and soap after a while. While using soap avoid using any soap which contains ammonia (which can badly damage furniture).
Along with cleaning also polish your furniture after cleaning. Polish will not only protect your furniture but will also maintain its shining surface. But there is also one thing that should be taken care of and that is any polish that contains too much alcohol is also damageable for wood furniture.
Re-oil, re-wax Furniture
After a while furniture becomes over-dry then you should re-oil it. Apply furniture oil and leave it to soak for 10-15 minutes. After applying protective oil wait 12-24 hours before using furniture.
If your furniture contains a wax layer, then you should re-wax it when requires. It will protect it and bring its shinning back.
Treat Furniture well
You should take care of the furniture and avoid things which can damage it. There are a lot of things like putting hot cups or other things on them. Heat damages furniture you should avoid such habits. If you need to put any hot object on it then put a trivet or potholder under it.Always set your furniture balanced, if one side is not touching ground equally as the other does, furniture will lose its original shape.