Choose an interior wood stain based on the color you desire and the type of hardwood flooring you have.
How to floor varnish.
When making the strokes try to follow the wood grain.
Fill in any gaps in the floorboards if you need to or want to.
Start at one end of the room and sand with the grain.
Let the dust settle vacuum it up and then wipe down your floor with white spirit.
Apply in sections which are no larger than 4 to 5 square feet.
How to prepare varnished floors lightly sand your floor with 120 grit sandpaper.
Use a long handled roller to spread the varnish first in the same direction as the grain then across.
This will ensure that the varnish looks natural.
Use your brush to apply the new oil based varnish to the floor.
Use less coarse sandpaper usually around a 120 to 150 grit abrasive to get a lovely smooth finish.
If your old varnish is flaking off use a floor sander to sand back to the bare wood.
Apply the stain with a foam applicator pad in the direction of the wood grain.
Work one manageable area at a time such as four square feet.
Pour a small amount of varnish onto the floor starting in the corner farthest from the door.