I have hardwood floors and have refinished mine myself. This web site had very good answers. I have and do use many of the methods  they talk about. One comment I do want to make of my own is when you buy rugs for hardwood floors, use only natural rugs. No rugs with any type of rubber backing. This causes some kind of chemical reaction and will discolor the floor where the rug is. If you have every gone to look at new model homes and have seen a pink area in front of, say, the front door where a rugs may have been, that is from a rug having been there before. A rug will especially do that to a hardwood floor if it is in an area where sun can shine on it.

Very good point.