Uneven hardwood floor stain can not only be unsightly, it can actually lower your home's value. Fortunately you can correct this problem with just a little bit of work and some time.
Step 1 - Lightly Sand the Area
You will need to sand the area that has the uneven stain on it. You want to lightly sand. If you sand too much, you will end up with an uneven surface, which is just as bad as an uneven stain. The sanding simply removes the coating in that area and will remove some of the stain as well.
Step 2 - Restain the Area
Even if the floor looks right after you've sanded it, you will still need to apply a small amount of stain. This will allow the stain to penetrate in to the wood and will ensure an even finish. Don't go overboard, and only use a very small amount of stain on the dry rag.
Step 3 - Allow Dry Time
Wait for the stain to completely permeate the wood by giving it at least 2 days to fully dry. This way if you need to add more stain, you can do so.
Step 4 - Seal the Floor
Once the stain is correct and set, you can seal the floor to protect the finish.