How can I effectively fill the gaps between wooden floorboards?

To effectively fill gaps between wooden floorboards, you can use wood filler, caulk, or rope. First, clean the gaps and remove any debris. Then, apply the filler or caulk into the gaps using a putty knife or your fingers. For a more rustic look, you can also insert rope into the gaps and seal it with a clear sealant. Make sure to let the filler dry completely before sanding and refinishing the floor.